[Klarna] Improve handling of unsupported merchant account countries about woocommerce-gateway-stripe

[james-allan]

TBD. Maybe add a note on the payment methods tab and don't display the payment method on the checkout page. Similar to what we do when the store currency isn't supported by the payment method.

Yeah I think that makes sense. FWIW, WooPayments do the same thing - they display Klarna and in the description it says that only transactions in USD are accepted.

Let's take the merchant country limitations of other payment methods into account when considering how to approach this.

I don't know if I've misunderstood this comment but it was my understanding that other payment methods (like GiroPay) require the store currency to be set to Euros to be enabled. That is different from how WooPayments works. They let you enable anything and then only show eligible payment methods on the checkout.

I think ideally we'd do something similar for all our payment methods. I think I recall talking about this at the meetup but there's a seperate issue for that here: #2970