fix(ci): configure Mock.load_team_config to return dict in proxy_utils test

The test_add_key_or_team_level_spend_logs_metadata_to_request test was
failing because proxy_config.load_team_config() returned a bare Mock
instead of a dict, causing Mock.keys() to be non-iterable.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/proxy_unit_tests/test_proxy_utils.py

@@ -178,6 +178,7 @@ async def test_add_key_or_team_level_spend_logs_metadata_to_request(
         team_metadata=team_metadata,
     )
     proxy_config = Mock()
+    proxy_config.load_team_config.return_value = {}
 
     data = {"metadata": {}}
     if request_tags is not None: