Fix window size issue of ES. (#5175)

### What problem does this PR solve?

#5152

### Type of change

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

graphrag/utils.py

     src_ids = []
     flds = ["entity_kwd", "entity_type_kwd", "from_entity_kwd", "to_entity_kwd", "weight_int", "knowledge_graph_kwd", "source_id"]
     bs = 256
-    for i in range(0, 10000, bs):
+    for i in range(0, 39*bs, bs):
         es_res = settings.docStoreConn.search(flds, [],
                                  {"kb_id": kb_id, "knowledge_graph_kwd": ["entity", "relation"]},
                                  [],