fix(cicd): drop obsolete async refresh locks auto-prune test

Commit dfb2524 intentionally reverted _async_refresh_locks from a
WeakValueDictionary back to a regular Dict so the per-key asyncio.Lock
identity is stable across concurrent callers — preserving
single-flight semantics. The test asserting that the dict shrinks
back to 0 after refreshes was added when the WeakValueDictionary
backing was still in place; it now contradicts the deliberate design
and is failing CI.

tests/test_litellm/llms/vertex_ai/test_vertex_llm_base.py

@@ -1778,51 +1778,9 @@ class TestVertexBase:
             f"found {len(vertex_base._background_refresh_tasks)}"
         )
 
-    @pytest.mark.asyncio
-    async def test_async_refresh_locks_auto_pruned_when_unused(self):
-        """Locks must be released from _async_refresh_locks once no coroutine
-        holds them — backed by a WeakValueDictionary so high-cardinality
-        deployments do not retain a Lock per credential key forever."""
-        import gc
-
-        from google.auth.credentials import TokenState
-
-        vertex_base = VertexBase()
-
-        for i in range(10):
-            mock_creds = MagicMock()
-            mock_creds.token = f"refreshed-{i}"
-            mock_creds.token_state = TokenState.FRESH
-            mock_creds.project_id = f"project-{i}"
-            mock_creds.quota_project_id = f"project-{i}"
-
-            credentials = {"type": "service_account", "project_id": f"project-{i}"}
-
-            with (
-                patch.object(
-                    vertex_base,
-                    "load_auth",
-                    return_value=(mock_creds, f"project-{i}"),
-                ),
-                patch.object(vertex_base, "refresh_auth"),
-            ):
-                await vertex_base._ensure_access_token_async(
-                    credentials=credentials,
-                    project_id=f"project-{i}",
-                    custom_llm_provider="vertex_ai",
-                )
-
-        gc.collect()
-
-        assert len(vertex_base._async_refresh_locks) == 0, (
-            f"Expected 0 lingering locks after refreshes completed, "
-            f"found {len(vertex_base._async_refresh_locks)}"
-        )
-
     @pytest.mark.asyncio
     async def test_async_refresh_lock_shared_while_in_use(self):
-        """Concurrent callers for the same key must coordinate on the same lock
+        """Concurrent callers for the same key must coordinate on the same lock."""
-        even with a WeakValueDictionary backing store."""
         vertex_base = VertexBase()
         key = ("creds", "project-1")