Bug: [FIX] Fix Mca create for v2



### Feature Description

fix merchant connector account create for v2 , by handling the case where defaull fallback is null ,while updating the it

### Possible Implementation

fix merchant connector account create for v2 , by handling the case where defaull fallback is null ,while updating the it

### Have you spent some time checking if this feature request has been raised before?

- [X] I checked and didn't find a similar issue

### Have you read the Contributing Guidelines?

- [X] I have read the [Contributing Guidelines](https://github.com/juspay/hyperswitch/blob/main/docs/CONTRIBUTING.md)

### Are you willing to submit a PR?

Yes, I am willing to submit a PR!
diff --git a/crates/router/src/core/admin.rs b/crates/router/src/core/admin.rs
index 553de8c5608..ab20c1c68bf 100644
--- a/crates/router/src/core/admin.rs
+++ b/crates/router/src/core/admin.rs
@@ -4204,16 +4204,19 @@ impl BusinessProfileWrapper {
     pub fn get_default_fallback_list_of_connector_under_profile(
         &self,
     ) -> RouterResult<Vec<routing_types::RoutableConnectorChoice>> {
-        use masking::ExposeOptionInterface;
-        self.profile
-            .default_fallback_routing
-            .clone()
-            .expose_option()
-            .parse_value::<Vec<routing_types::RoutableConnectorChoice>>(
-                "Vec<RoutableConnectorChoice>",
-            )
-            .change_context(errors::ApiErrorResponse::InternalServerError)
-            .attach_printable("Merchant default config has invalid structure")
+        let fallback_connectors =
+            if let Some(default_fallback_routing) = self.profile.default_fallback_routing.clone() {
+                default_fallback_routing
+                    .expose()
+                    .parse_value::<Vec<routing_types::RoutableConnectorChoice>>(
+                        "Vec<RoutableConnectorChoice>",
+                    )
+                    .change_context(errors::ApiErrorResponse::InternalServerError)
+                    .attach_printable("Business Profile default config has invalid structure")?
+            } else {
+                Vec::new()
+            };
+        Ok(fallback_connectors)
     }
     pub fn get_default_routing_configs_from_profile(
         &self,

## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
 fix merchant connector account create for v2 , by handling the case where defaull fallback is null ,while updating the it


### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

<!--
Provide links to the files with corresponding changes.

Following are the paths where you can find config files:
1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
-->


## Motivation and Context
<!--
Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.

If you don't have an issue, we'd recommend starting with one first so the PR
can focus on the implementation (unless it is an obvious bug or documentation fix
that will have little conversation).
-->


## How did you test it?
- Create a Organization
```
curl --location 'http://localhost:8080/v2/organization' \
--header 'Content-Type: application/json' \
--header 'api-key: test_admin' \
--data '{
    "organization_name": "my_org"
}'
```

- Create a MA and then a profile
```
curl --location 'http://localhost:8080/v2/accounts' \
--header 'Content-Type: application/json' \
--header 'api-key: test_admin' \
--data '{
    "merchant_name": "cloth_seller",
    "organization_id": "org_HzxLj0Nf9v9H0iKQDCFZ"
}'
```
```
curl --location 'http://localhost:8080/v2/profiles' \
--header 'x-merchant-id: cloth_seller_ea0VXdPfRBFXr2hd2vHL' \
--header 'Content-Type: application/json' \
--header 'api-key: test_admin' \
--data-raw '{
    "profile_name": "business",
    "return_url": "https://google.com/success",
    "enable_payment_response_hash": true,
    "redirect_to_merchant_with_http_post": false,
    "webhook_details": {
        "webhook_version": "1.0.1",
        "webhook_username": "ekart_retail",
        "webhook_password": "password_ekart@123",
        "webhook_url": "https://webhook.site",
        "payment_created_enabled": true,
        "payment_succeeded_enabled": true,
        "payment_failed_enabled": true
    },
    "metadata": null,
    "order_fulfillment_time": 900
}'
```

- Create a MCA, it should be successfully created

```
Response
{
    "connector_type": "payment_processor",
    "connector_name": "adyen",
    "connector_label": "adyen_business",
    "id": "mca_019193515e77726687170b4d4dac2887",
    "profile_id": "pro_YtPK4bYZ86jideG8KEBn",
    "connector_account_details": {
        "auth_type": "BodyKey",
        "api_key": "AQEqhmfxK43MaR1Hw0m/n3Q5qf3VYp5eHZJTfEA0SnT87rrwTHXDVGtJ+kfCEMFdWw2+5HzctViMSCJMYAc=-3z4LNx7vk7s3KOZ6PMgPPx2HKrP9XfzQWMxU0OtdxTc=-suZ%I8NM9qv+?up}",
        "key1": "JuspayDEECOM",
        "api_secret": "AQEzgmDBbd+uOlwd9n6PxDJo8rXOaKhCAINLVnwY7G24jmdSuuL0Salp1G0BJE6opzqZqP6rEMFdWw2+5HzctViMSCJMYAc=-bn/JeFXqIxxfhhy67PE2sTZctbqzqe+fU0JprcbCEmE=-:M><zzc+t9Ne#2eb"
    },
    "payment_methods_enabled": [
        {
            "payment_method": "card_redirect",
            "payment_method_types": [
                {
                    "payment_method_type": "card_redirect",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": 1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                }
            ]
        },
        {
            "payment_method": "card",
            "payment_method_types": [
                {
                    "payment_method_type": "credit",
                    "payment_experience": null,
                    "card_networks": [
                        "Visa",
                        "Mastercard"
                    ],
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "debit",
                    "payment_experience": null,
                    "card_networks": [
                        "Visa",
                        "Mastercard"
                    ],
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                }
            ]
        },
        {
            "payment_method": "wallet",
            "payment_method_types": [
                {
                    "payment_method_type": "google_pay",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "apple_pay",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "we_chat_pay",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "ali_pay",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "paypal",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "mb_way",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                }
            ]
        },
        {
            "payment_method": "pay_later",
            "payment_method_types": [
                {
                    "payment_method_type": "klarna",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "affirm",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "afterpay_clearpay",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "walley",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                }
            ]
        },
        {
            "payment_method": "bank_redirect",
            "payment_method_types": [
                {
                    "payment_method_type": "giropay",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "ideal",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "eps",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "bancontact_card",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "przelewy24",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "sofort",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "blik",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "trustly",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "online_banking_finland",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "online_banking_poland",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                }
            ]
        },
        {
            "payment_method": "bank_transfer",
            "payment_method_types": [
                {
                    "payment_method_type": "ach",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "sepa",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "bacs",
                    "payment_experience": "redirect_to_url",
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                }
            ]
        },
        {
            "payment_method": "bank_debit",
            "payment_method_types": [
                {
                    "payment_method_type": "ach",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "sepa",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "bacs",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                },
                {
                    "payment_method_type": "becs",
                    "payment_experience": null,
                    "card_networks": null,
                    "accepted_currencies": null,
                    "accepted_countries": null,
                    "minimum_amount": -1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true
                }
            ]
        }
    ],
    "connector_webhook_details": {
        "merchant_secret": "",
        "additional_secret": null
    },
    "metadata": {
        "status_url": "https://2753-2401-4900-1cb8-2ff9-24dd-1ccf-ed12-b464.in.ngrok.io/webhooks/merchant_1678699058/globalpay",
        "account_name": "transaction_processing",
        "acquirer_bin": "438309",
        "pricing_type": "fixed_price",
        "acquirer_merchant_id": "00002000000"
    },
    "disabled": null,
    "frm_configs": null,
    "applepay_verified_domains": null,
    "pm_auth_config": null,
    "status": "active",
    "additional_merchant_data": null
}
```
## Checklist
<!-- Put an `x` in the boxes that apply -->

- [ ] I formatted the code `cargo +nightly fmt --all`
- [ ] I addressed lints thrown by `cargo clippy`
- [ ] I reviewed the submitted code
- [ ] I added unit tests for my changes where possible
