Hosted Forms Throw Generic Error

Currently, hosted forms (both ACH and CC) throw a generic error:
`We encountered an error processing your payment method. Please verify your details and try again.`

This error was present in 8.x-3.0 as well, which might mean there was a change in how iATS provides the hosted form, or a regression within our module that we need to fix.

For now, `Direct Submission` is the way to accept payments with this module.

If you have any more details, requests, or experiences to add, please do. Otherwise we will dig in deeper when time allows.