refactor: Stop tracing service gracefully

src/backend/base/langflow/services/tracing/service.py

@@ -66,9 +66,12 @@ class TracingService(Service):
         try:
             self.running = False
             await self.flush()
+            # check the qeue is empty
+            if not self.logs_queue.empty():
+                await self.logs_queue.join()
             self.worker_task.cancel()
-            if self.worker_task:
-                await self.worker_task
+            self.worker_task = None
+
         except Exception as e:
             logger.error(f"Error stopping tracing service: {e}")