reduce interval of task executor heart beat (#2308)

### What problem does this PR solve?


### Type of change

- [x] Performance Improvement
- [ ] Other (please describe):

rag/svr/task_executor.py

@@ -404,7 +404,7 @@ def report_status():
             REDIS_CONN.set_obj("TASKEXE", obj, 60*2)
         except Exception as e:
             print("[Exception]:", str(e))
-        time.sleep(60)
+        time.sleep(30)
 
 
 if __name__ == "__main__":