[BUG] GlobalPay throws 501 for mandates

below function is the culprit:

```rs
fn get_payment_method_data(
    item: &PaymentsAuthorizeRouterData,
    brand_reference: Option<String>,
) -> Result<PaymentMethodData, Error> {
    match &item.request.payment_method_data {
        payment_method_data::PaymentMethodData::Card(ccard) => {
            Ok(PaymentMethodData::Card(requests::Card {
                number: ccard.card_number.clone(),
                expiry_month: ccard.card_exp_month.clone(),
                expiry_year: ccard.get_card_expiry_year_2_digit()?,
                cvv: ccard.card_cvc.clone(),
                account_type: None,
                authcode: None,
                avs_address: None,
                avs_postal_code: None,
                brand_reference,
                chip_condition: None,
                funding: None,
                pin_block: None,
                tag: None,
                track: None,
            }))
        }
        payment_method_data::PaymentMethodData::Wallet(wallet_data) => get_wallet_data(wallet_data),
        payment_method_data::PaymentMethodData::BankRedirect(bank_redirect) => {
            PaymentMethodData::try_from(bank_redirect)
        }
        _ => Err(errors::ConnectorError::NotImplemented(
            "Payment methods".to_string(),
        ))?,
    }
}
```

just because `MandatePayment` isn't covered, it falls back to the default case which throws `501`.


relevant docs:

- [Tokenization](https://developer.globalpay.com/api/payment-methods-tokenization#/Create/post-payment-method)
- [MIT](https://developer.globalpay.com/docs/MIT)
- [Recurring](https://developer.globalpay.com/docs/payments/recurring/credentials-on-file)
<think>
PR Context:
- Title: fix(connector): [globalpay] address 5xx in mandates by implementing tokenization flow
- Merged: None
- Files changed: 13 files
- Commits: 5 commits

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

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

## Description
<!-- Describe your changes in detail -->

This PR address 5xx during MIT payments in GlobalPay.
Previously, mandates through GlobalPay would throw a `501` just because the control flow would hit the default case during the `confirm` call:

```rs
fn get_payment_method_data(
    
</think>

To implement this, you'll need to modify:


(No detailed commit information available)
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