Whitescreen when user not found

[FelixMalfait]

I was going back to demo.twenty.com and since the database was reset it threw a "user not found" error. But this error wasn't properly interpreted by the frontend and I just had a full blank page. Instead I should have been logged out and sent to the login page (we should already have this mechanism for token expiration).

Maybe check if it's a proper AuthException being thrown in every case?

This probably happens to everyone who visits the demo website and comes back the following day.