Accepted credit cards not saved when creating or editing a payment processor
This change in 5.61 makes it so that if you create or save a payment processor, accepted_credit_cards is not saved correctly. The problem is that the save was changed to API 4, which doesn't properly handle JSON and accepted_credit_cards is one of the few JSON fields we have.
I think for now, we should just go back to API 3 and then we can switch back to API 4 when the JSON issue is resolved.