fix: fix linting error

Author: krrishdholakia

litellm/proxy/management_endpoints/ui_sso.py

@@ -11,6 +11,7 @@
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union, cast
 
 from fastapi import APIRouter, Depends, HTTPException, Request, status
+from fastapi.responses import RedirectResponse
 
 import litellm
 from litellm._logging import verbose_proxy_logger