Country eligibility check for BNPL messaging element on product/cart pages

[frosso]

Describe the bug

The BNPL messaging element is rendered in a few pages:

• Product pages
• Block-based cart & checkout
• Shortcode-based cart & checkout

As it currently stands, the implementation for checkout pages is different than the ones on cart & product pages.
On the checkout pages, the eligibility check is done on the selected customer's billing country (or the store's country), and whether that country is allowed for the BNPL payment methods.

On the product & cart pages, this check doesn't seem to be implemented.

So, if the customer's billing country is not supported by any of the enabled BNPL methods (e.g.: billing country CN), the BNPL messaging element will still attempt to render, and then fail.
Sometimes, this failure is just present in the browser's console.
Other times, this failure can be visible in the store's front-end (if you're admin and have error logging enabled).

We should implement the same checks in the product & cart implementations for BNPL messaging eligibility.

To Reproduce

1. Add a product to the cart
2. Go to checkout, select CN as the billing country
3. Go back to the product page or the cart page

Actual behavior

The BNPL messaging attempts to render, but fails.

Screenshots

Expected behavior

The BNPL messaging element shouldn't render if the country is not supported.

Additional context

p1736962049965999-slack-CU6SYV31A

[anu-rock]

Triaging alert: This issue concerns checkout and BNPL. Sending it to @Automattic/heisenberg as per Pc2DNy-3z-p2 by adding the relevant focus label. cc @FangedParakeet

[timur27]

There's also an issue of global intermittently being unavailable during the execution when opening the block-based cart. I might create a separate PR for that, depending on what the change will look like.

Screen.Recording.2025-02-21.at.11.57.25.mov

UPDATE: I added a check for global before the execution.