No iDEAL issuer input field with Pronamic payment method

[rvdsteege]

With iDEAL Advanced, the Pronamic payment method used to add the issuer input field at checkout. Since Pronamic Pay version 9.0.0 this is no longer the case. This now results in an error message:

BIC invalid. Field generating error: issuerID

The $gateway->payment_method_is_required() was used to set the payment method to iDEAL in this case:

• https://github.com/pronamic/wp-pay-core/blob/0cdc62c78b59cc71608b0d70abbab3d16f335713/src/Core/Gateway.php#L434-L447

We've removed this method, maybe we can find an other solution to:

1. make this work or;
2. prevent the gateway configuration from being used at all if it does not support the Pronamic (null) payment method.

[remcotolsma]

I think this problem is so small that it has no added value to come up with a solution for this. Most users will now also use the iDEAL gateway within the extensions for the iDEAL payment method.