Changes:
- Changed the message logged when a Vanta integration has an error to a
warning so our Papertrail alerts will be triggered whenever a Vanta
integration has an error.
The intention is to have Vanta stop showing warnings for missing MFA on
API-only users. It's not clear if setting `UNSUPPORTED` is the correct
solution, but it does seem more accurate than setting the `mfaEnabled`
to `true`.