Bug: [BUG]: [Adyen] Remove payment_method_type as required field in MIT



### Bug Description

Currently payment_method_type is a required field in MIT payments, which might not be the case all the time, so we need to handle this scenario

### Expected Behavior

MIT payments should work regardless payment_method_type was provided or not

### Actual Behavior

Currently payment_method_type is a required field in MIT payments, which might not be the case all the time, so we need to handle this scenario

### Steps To Reproduce

Provide an unambiguous set of steps to reproduce this bug. Include code or configuration to reproduce, if relevant.
1. Go to '...'
2. Click on '....'
3. Scroll down to '....'


### Context For The Bug

_No response_

### Environment

Are you using hyperswitch hosted version? Yes/No
If yes, please provide the value of the `x-request-id` response header to help us debug your issue.

If not (or if building/running locally), please provide the following details:
1. Operating System or Linux distribution:
2. Rust version (output of `rustc --version`): ``
3. App version (output of `cargo r --features vergen -- --version`): ``


### Have you spent some time checking if this bug 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/connector/adyen/transformers.rs b/crates/router/src/connector/adyen/transformers.rs
index d320475e61c..d56ec571ac6 100644
--- a/crates/router/src/connector/adyen/transformers.rs
+++ b/crates/router/src/connector/adyen/transformers.rs
@@ -2528,16 +2528,14 @@ impl<'a>
         let browser_info = None;
         let additional_data = get_additional_data(item.router_data);
         let return_url = item.router_data.request.get_return_url()?;
-        let payment_method_type = item
-            .router_data
-            .request
-            .payment_method_type
-            .as_ref()
-            .ok_or(errors::ConnectorError::MissingPaymentMethodType)?;
+        let payment_method_type = item.router_data.request.payment_method_type;
         let payment_method = match mandate_ref_id {
             payments::MandateReferenceId::ConnectorMandateId(connector_mandate_ids) => {
                 let adyen_mandate = AdyenMandate {
-                    payment_type: PaymentType::try_from(payment_method_type)?,
+                    payment_type: match payment_method_type {
+                        Some(pm_type) => PaymentType::try_from(&pm_type)?,
+                        None => PaymentType::Scheme,
+                    },
                     stored_payment_method_id: Secret::new(
                         connector_mandate_ids.get_connector_mandate_id()?,
                     ),

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

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

## Description
<!-- Describe your changes in detail -->
remove mandatory payment_method_type check in MIT, as we won't necessarily have this in CIT

### 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).
-->
https://github.com/juspay/hyperswitch/issues/5245

## How did you test it?
<!--
Did you write an integration/unit/API test to verify the code changes?
Or did you test this change manually (provide relevant screenshots)?
-->
### CIT payment via Adyen without payment_method_type
```
curl --location 'http://localhost:8080/payments' \
--header 'Accept: application/json' \
--header 'Content-Type: application/json' \
--header 'api-key: dev_FdbwTgkrJgCahVeugTVGJ3KWbS0UiIADoLlJoMfP2gzxicfOqbJ3HXcjoP8fjr8I' \
--data-raw '{
    "amount": 1212,
    "currency": "USD",
    "confirm": true,
    "capture_method": "automatic",
    "customer_id": "adyen_test",
    "authentication_type": "no_three_ds",
    "return_url": "https://google.com",
    "email": "abc-ext.kylta@flowbird.group",
    "name": "Joseph Doe",
    "phone": "999999999",
    "phone_country_code": "+65",
    "description": "Its my first payment",
    "statement_descriptor_name": "Juspay",
    "statement_descriptor_suffix": "Router",
    "payment_method": "card",
    "payment_method_data": {
        "card": {
			"card_number": "4111111145551142",
			"card_exp_month": "03",
			"card_exp_year": "2030",
			"card_holder_name": "joseph Doe",
			"card_cvc": "737"
		}
    },
    "billing": {
        "address": {
            "state": "CA",
            "first_name": "John",
            "city": "San Francisco",
            "zip": "44545",
            "country": "US",
            "line1": "52 Julianastraat",
            "line2": "52 Julianastraat",
            "last_name": "Doe"
        },
        "phone": {
            "number": "8056594427",
            "country_code": "+91"
        }
    },
    "setup_future_usage": "off_session",
    "customer_acceptance": {
        "acceptance_type": "offline",
        "accepted_at": "1963-05-03T04:07:52.723Z",
        "online": {
            "ip_address": "in sit",
            "user_agent": "amet irure esse"
        }
    },
    "browser_info": {
        "user_agent": "Mozilla\/5.0 (iPhone NT 10.0; Win64; x64) AppleWebKit\/537.36 (KHTML, like Gecko) Chrome\/70.0.3538.110 Safari\/537.36",
        "accept_header": "text\/html,application\/xhtml+xml,application\/xml;q=0.9,image\/webp,image\/apng,*\/*;q=0.8",
        "language": "nl-NL",
        "color_depth": 24,
        "screen_height": 723,
        "screen_width": 1536,
        "time_zone": 0,
        "java_enabled": true,
        "java_script_enabled": true,
        "ip_address": "128.0.0.1"
    },
    "order_details": [
        {
            "product_name": "Apple iphone 15",
            "quantity": 1,
            "amount": 10,
            "account_name": "transaction_processing"
        },
        {
            "product_name": "Apple iphone 15",
            "quantity": 1,
            "amount": -100,
            "account_name": "transaction_processing"
        }
    ]
}'
```

### Recurring Payment MIT
```
curl --location 'http://localhost:8080/payments' \
--header 'Accept: application/json' \
--header 'Content-Type: application/json' \
--header 'api-key: dev_FdbwTgkrJgCahVeugTVGJ3KWbS0UiIADoLlJoMfP2gzxicfOqbJ3HXcjoP8fjr8I' \
--data-raw '{
    "amount": 1212,
    "currency": "USD",
    "confirm": true,
    "capture_method": "automatic",
    "customer_id": "scheme_test1",
    "authentication_type": "no_three_ds",
    "return_url": "https://google.com",
    "email": "abc-ext.kylta@flowbird.group",
    "name": "Joseph Doe",
    "phone": "999999999",
    "phone_country_code": "+65",
    "description": "Its my first payment",
    "statement_descriptor_name": "Juspay",
    "statement_descriptor_suffix": "Router",
    "billing": {
        "address": {
            "state": "CA",
            "first_name": "John",
            "city": "San Francisco",
            "zip": "44545",
            "country": "US",
            "line1": "52 Julianastraat",
            "line2": "52 Julianastraat",
            "last_name": "Doe"
        },
        "phone": {
            "number": "8056594427",
            "country_code": "+91"
        }
    },
    "off_session": true,
    "recurring_details": {
        "type":"payment_method_id",
        "data":"pm_7uWrqPlgdejkhaczULUY"
    },
    "order_details": [
        {
            "product_name": "Apple iphone 15",
            "quantity": 1,
            "amount": 10,
            "account_name": "transaction_processing"
        },
        {
            "product_name": "Apple iphone 15",
            "quantity": 1,
            "amount": -100,
            "account_name": "transaction_processing"
        }
    ]
}'
```

## Checklist
<!-- Put an `x` in the boxes that apply -->

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