Return 422 if user is not found or password is incorrect

## Return 422 if user is not found or password is incorrect

### Acceptance Criteria
1. OAuthController returns 422 if the username (email) is incorrect or the password is wrong.

### Tasks
- Change response status codes.
- Clean up the code.
- Add unit tests.

### Additional Notes
- None
I don't see a password being included in any request for this test. In fact the only request made is a GET request, which wouldn't include a password anyway.