fix update_by_api batch field issue (langgenius#10001)

Author: JohnJyong

api/controllers/service_api/dataset/document.py

@@ -230,7 +230,7 @@ def post(self, tenant_id, dataset_id, document_id):
         except ProviderTokenNotInitError as ex:
             raise ProviderNotInitializeError(ex.description)
         document = documents[0]
-        documents_and_batch_fields = {"document": marshal(document, document_fields), "batch": batch}
+        documents_and_batch_fields = {"document": marshal(document, document_fields), "batch": document.batch}
         return documents_and_batch_fields, 200