acquite download_condition lock

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

Author: varun-edachali-dbx

src/databricks/sql/cloudfetch/download_manager.py

@@ -131,4 +131,5 @@ def _shutdown_manager(self):
         self._pending_links = []
         self._download_tasks = []
         self._thread_pool.shutdown(wait=False)
-        self._download_condition.notify_all()
+        with self._download_condition:
+            self._download_condition.notify_all()