Fix ruff import grouping in api/auth.py

Remove extra blank line between third-party imports to satisfy
ruff isort rules.

Signed-off-by: Denys Fedoryshchenko <denys.f@collabora.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: nuclearcat

api/auth.py

@@ -9,7 +9,6 @@
 from typing import Optional
 
 import jwt as pyjwt
-
 from fastapi_users import exceptions, models
 from fastapi_users.authentication import (
     AuthenticationBackend,