fix bulk error for table method (#407)

### What problem does this PR solve?


Issue link:#366

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

rag/utils/es_conn.py

@@ -2,6 +2,7 @@ import re
 import json
 import time
 import copy
+
 import elasticsearch
 from elastic_transport import ConnectionTimeout
 from elasticsearch import Elasticsearch