BAU Add logging for failed IDP response statuses
BAU Add logging for failed IDP response statuses

We've had a few users end up unexpectedly on the fail page when after
logging in to an IDP. This will happen if the IDP sends back a few
different statuses. We currently don't have any insight into what they
are. This should help.

alphagov/verify-frontend,alphagov/verify-frontend,alphagov/verify-frontend,alphagov/verify-frontend