When we're fetching the payment intent via PaymentIntentValidator in StripeSCA#purhcase (to capture it), we want it to fail loudly if it's not in "requires_capture" state. We're now also re-using the same PaymentIntentValidator service to check if payment processing was *successful*, in which case we need it *not* to fail loudly if the state == "succeeded", eg != "requires_capture".
We observed invalid payment states in Bugsnag but we don't actually know
in which state the payment intent was in. From the context we can guess
that it was "succeeded" but it would be good to validate this. And in
the future it would be good to know if there are other invalid states we
can end up in.
The notification to Bugsnag happens in another part of the code.
