Display OIDC configuration errors to the end user

[BruceMacD]

Describe the bug

When there is an error is OIDC configuration it is logged at the debug level on the server. This is good for self-hosting, but in the case of the hosted service there is no way for the end-user to see the error from their identity provider.

Expected behavior

Display an error hint to the end-user when an OIDC login fails.