Feat: GraphRAG handle cancel gracefully (#11061)

### What problem does this PR solve?

 GraghRAG handle cancel gracefully. #10997.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

rag/flow/pipeline.py

@@ -41,7 +41,7 @@ class Pipeline(Graph):
                 self._doc_id = None
 
     def callback(self, component_name: str, progress: float | int | None = None, message: str = "") -> None:
-        from rag.svr.task_executor import TaskCanceledException
+        from common.exceptions import TaskCanceledException
         log_key = f"{self._flow_id}-{self.task_id}-logs"
         timestamp = timer()
         if has_canceled(self.task_id):