Show payment methods available in the PMC on settings page

[Mayisha]

In the current PMC implementation, we are syncing the enabled/disable payment methods between plugin settings and Stripe dashboard. But the list of available payment methods in plugin settings is not aligned with the payment method configuration. As a result, we show some payment methods in the settings page that are not available in the PMC.

Changes proposed in this Pull Request:

• Retrieve available payment methods from PMC when get_upe_available_payment_methods is called.
• Aligned with the cache implementation.
• If pmc is not enabled, fall back to the previous code.

Testing instructions

• Go to your Stripe settings page and connect to a Stripe account that does not support some payment methods (i.e, I have tested with an Australian Stripe account)
• In develop, go to the payment methods tab and notice that you have OXXO, Boleto, ACSS available in the payment method list.

• Go to the payment methods page in your Stripe dashboard and choose the payment configuration under WooCommerce.
• Notice that, you do not have OXXO/Boleto/ACSS available here.
• Now set your store currency to CAD and enable ACSS (Pre-authorized debit).
• Click Save and refresh your page.
• Notice that, ACSS is still disabled.
• In your store logs, you will find the error Error: acss_debit is not available to this merchant.
• Now checkout to this branch and refresh the Stripe settings page.
• Confirm that you don't see the unsupported payment methods anymore.
• Try to enable/disable a few methods and confirm that the changes persists in your plugin settings page and also synced in the Stripe dashboard.

[diegocurbelo]

The implementation looks good, the only comment is renaming the get_upe_available_payment_methods function in WC_Stripe_Payment_Method_Configurations

[daledupreez]

@Mayisha, could you add more context to the PR so we can test it before @diegocurbelo is available?

[Mayisha]

@daledupreez I have added the description and addressed the feedback.

[daledupreez]

It looks like there are a number of legitimate unit test failures that we need to resolve before we can merge this.

@Mayisha, let me know if you'd like to hand over work on getting the tests working.

[daledupreez]

I have one concern here: we're forcing two refreshes of the PMC from Stripe when $is_upe_enabled, as we're supplying $force_refresh = true to both $this->gateway->get_upe_available_payment_methods() and $this->gateway->get_upe_enabled_payment_method_ids( true ). We should only trigger one re-fetch.

Suggested change

	$available_payment_method_ids = $is_upe_enabled ? $this->gateway->get_upe_available_payment_methods( true ) : WC_Stripe_Helper::get_legacy_available_payment_method_ids();
	$ordered_payment_method_ids = $is_upe_enabled ? WC_Stripe_Helper::get_upe_ordered_payment_method_ids( $this->gateway ) : $available_payment_method_ids;
	$enabled_payment_method_ids = $is_upe_enabled ? $this->gateway->get_upe_enabled_payment_method_ids( true ) : WC_Stripe_Helper::get_legacy_enabled_payment_method_ids();
	// Note that we specify the $force_refresh parameter for this fetch only, and not when fetching enabled payment methods below.
	$available_payment_method_ids = $is_upe_enabled ? $this->gateway->get_upe_available_payment_methods( true ) : WC_Stripe_Helper::get_legacy_available_payment_method_ids();
	$ordered_payment_method_ids = $is_upe_enabled ? WC_Stripe_Helper::get_upe_ordered_payment_method_ids( $this->gateway ) : $available_payment_method_ids;
	$enabled_payment_method_ids = $is_upe_enabled ? $this->gateway->get_upe_enabled_payment_method_ids( false ) : WC_Stripe_Helper::get_legacy_enabled_payment_method_ids();

[daledupreez]

I am not clear on why this code is not checking/calling self::is_enabled(). We are checking that in get_upe_enabled_payment_method_ids() below, and in the current calling code, so I am not sure why we're skipping the check here.

My initial suspicion is that is_enabled() is checking for write permissions, where we only need to read what functions are available for the account. But then I got confused across the various cases.

[daledupreez]

This removal is causing unit test failures, and I am not sure how it's related to fixing the original issue.
At the very least we need to fix the unit test failures, but it feels like this should be something tackled by a different PR.