fix: task_executor bug fix (#7253)

### What problem does this PR solve?

The lock is not released correctly when task_exectuor is abnormal

### Type of change

- [ ] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

rag/svr/task_executor.py

                         REDIS_CONN.delete(consumer_name)
         except Exception:
             logging.exception("report_status got exception")
+        finally:
+            redis_lock.release()
         await trio.sleep(30)
 
 
             stop_event.wait(60)
         except Exception:
             logging.warning("recover_pending_tasks got exception")
+        finally:
+            redis_lock.release()
 
 
 async def main():