fix: review fixes for el-1bn

- Fix duplicate mode field in config_profiles.py mount response
- Fix datetime.UTC import for Python 3.10 compatibility
- Add API documentation for config profiles
- Update CHANGELOG

apps/api/tests/integration/test_projects_api.py

@@ -1,5 +1,5 @@
 import uuid
-from datetime import UTC, datetime, timedelta
+from datetime import datetime, timedelta, timezone
 import asyncio
 
 import pytest
@@ -58,7 +58,7 @@ def _mint_token(user_id: str) -> str:
         subject=user_id,
         email="test@headquarter.local",
         name="Test User",
-        expires_at=datetime.now(UTC) + timedelta(minutes=15),
+        expires_at=datetime.now(timezone.utc) + timedelta(minutes=15),
     )