fix get dataset error in dataflow run function

Signed-off-by: ZhangXiaozheng <zhang__xiaozheng@outlook.com>

Author: zhang-x-z

fluid/api/fluid_dataflow.py

@@ -224,7 +224,7 @@ def run(self, run_id, ttl_seconds_after_finished=constants.DEFAULT_DATAFLOW_TIME
         The FlowHandle object which may track the flow's status.
         """
         try:
-            dataset = self.fluid_client.get_dataset(self.dataset_name)
+            dataset = self.fluid_client.get_dataset(self.dataset_name, self.dataset_namespace)
         except Exception as e:
             raise RuntimeError(f"failed to get dataset {self.dataset_name}: {e}")