[ECE] Fix payment method title for orders paid with ECE button

[Mayisha]

The payment method title is set to Credit/Debit Card instead of Apple Pay or Google Pay when purchased via the express checkout button.

Steps to reproduce

• Enable the ECE feature flag (return true from is_stripe_ece_enabled function or in your database add an option _wcstripe_feature_ece and set yes as the value).
• Checkout to the branch of either Implement ECE for payment processing on block checkout page #3439 or Integrating ECE to shortcode checkout #3436 (checkout to develop if any of the mentioned PR is merged)
• As a shopper add a product to your cart and go to the checkout page.
• Complete the purchase with Google/Apple pay button.
• Notice that on the order confirmation page, the payment method is Credit/Debit Card instead of Apple Pay or Google Pay.

• As an admin, go to the order edit page and notice that the payment method is Card.

Expected behavior

• The payment method title should be Google Pay or Apple Pay similar to how it is set when paid with PRB buttons.

[james-allan]

I fixed this issue on my Pay For Order PR #3440. In that PR I added a new helper to map the payment button type to a payment method title.

I'll take this one.