[Bug Report] Error reporting failure for non-constraint issues

[DeadlyFirex]

Describe the bug Error reporting fails when a non-constraint related issue happens in /admin/user/add.

To Reproduce Steps to reproduce the behavior:

1. Authenticate as an admin
2. Create a body with a username that already exists.
3. Send a POST request to /admin/user/add
4. See error

Expected behavior The endpoint properly reports the issue.

Actual behavior The server fails to represent the issue, since a constraint issue is assumed.

Screenshots N/A

Operating System: N/A

Additional context N/A

[DeadlyFirex]

Fixed in faa83f931403f53b8aa823d89b8dca21d37f3962