Fix empty space for express checkout container

[Mayisha]

Fixes #3470

Changes proposed in this Pull Request:

• Return 'false' for 'canMakePayment' only when express checkout is disabled.
• Added 'checkPaymentMethodIsAvailable' function for blocks (same as WooPayments)

Reproduce the issues

• 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).
• Enable Google Pay/ Apple Pay from the Stripe settings page.
• Go to localhost:8082, add a product to your cart and check the block cart and checkout page.
• Notice that there is an empty express checkout section displayed. (Issue 1)
• Use a publicly accessible link for your site (jurassic tube or ngrok).
• Add many or expensive products to your cart so that the cart total is beyond $1,000,000.00 USD (or 1.000.000,00 EUR). - Notice that an empty express checkout section is loaded. (Issue 2)
• Now disable Google Pay/ Apple Pay from the Stripe settings page.
• Add a product to your cart and check the block cart and checkout page.
• Notice that there is an empty express checkout section displayed. (Issue 3)

Screenshots

Cart page

Checkout page

Testing instructions

Follow the steps to reproduce the issues in this branch and confirm that the empty express checkout section is not displayed anymore.

[annemirasol]

FYI I see this warning in the console:

Warning: You are importing createRoot from "react-dom" which is not supported. You should instead import it from "react-dom/client".