test(proxy): import Final in the line's batch endpoint tests

The tests picked from #47067 annotate module constants with Final, which main's copy imports and this line's did not, so the module failed to import on Python 3.12.

tests/test_litellm/proxy/batches_endpoints/test_endpoints.py

@@ -35,7 +35,7 @@ import logging
 from contextlib import ExitStack
 from dataclasses import dataclass
 from datetime import datetime, timedelta, timezone
-from typing import Any, Dict, Optional
+from typing import Any, Dict, Final, Optional
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import httpx