Add subscriptions support to Bacs

[asumaran]

Closes #3798

Changes proposed in this Pull Request:

The changes here are quite simple. The most important one is enabling Bacs support for subscriptions. By default, Bacs should work well for the subscription cases listed below, except for subscriptions with a free trial. For now, the Bacs payment method is being disabled for subscriptions with a free trial as it will be addressed separately. More info here.

Testing instructions

Install the WooCommerce Subscriptions and test checking out using following subscription variatons.

• Simple subscription.
  • Virtual product.
  • Physical product.
• Variable subscription.
  • Virtual products.
  • Physical products.
• Simple subscription with:
  • Free Trial

    {
      "error": {
        "message": "Your account isn't configured to directly use SetupIntents to create Mandates for Bacs Direct Debits. See https://stripe.com/docs/payments/payment-methods/bacs-debit to learn more, or contact us through https://support.stripe.com/contact/.",
        "param": "deferred_intent.payment_method_types",
        "request_log_url": "https://dashboard.stripe.com/acct_1Ja916HJAl4h87JO/test/logs/req_D2rNbNMZcnr08C?t=1740691770",
        "type": "invalid_request_error"
      }
    }
    

  • Sign Up Fee.
  • Free trial with Sign Up Fee

It would be nice to test with shortcode checkout and the checkout block.

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• Covered with tests (or have a good reason not to test in description ☝️)
• Tested on mobile (or does not apply)

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• Added testing instructions to the Release Testing Instructions wiki page (or does not apply)
• Added the needs docs label (or does not apply)
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