fix(proxy): keep the team-admin field allow-list importable on python 3.10

assert_never landed in typing in 3.11, so importing it from typing broke the
3.10 import smoke job and the py310 typing gate. Take it from typing_extensions
like the rest of the proxy does.

Also drop /team/update from test_neighbouring_team_routes_stay_closed. The route
is self-managed now, so the coarse gate admits the caller and update_team decides,
which the sibling test in the same file already asserts.

Claude-Session: https://claude.ai/code/session_018PUCupsaarVLJy4iDFx256

litellm/proxy/management_endpoints/team_admin_field_permissions.py

@@ -3,10 +3,11 @@
 from collections.abc import Mapping
 from dataclasses import dataclass
 from types import MappingProxyType
-from typing import Final, Literal, TypeAlias, assert_never
+from typing import Final, Literal, TypeAlias
 
 from fastapi import HTTPException
 from pydantic import TypeAdapter, ValidationError
+from typing_extensions import assert_never
 
 from litellm._logging import verbose_proxy_logger
 from litellm.models.team import LiteLLM_TeamTable

tests/test_litellm/proxy/auth/test_route_checks.py

@@ -3828,7 +3828,6 @@ def test_team_disable_logging_stays_proxy_admin_only():
     "route",
     [
         "/team/06bda574-5ca9-43d3-beb8-3b23c2f17112",
-        "/team/update",
         "/team/06bda574-5ca9-43d3-beb8-3b23c2f17112/model/add",
     ],
 )