Fix: search issue for graphrag (#3546)

### What problem does this PR solve?

#3538

### Type of change

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

graphrag/search.py

 
         ent_res = self.dataStore.search(src, list(), condition, [matchText, matchDense, fusionExpr], OrderByExpr(), 0, 32, idxnm, kb_ids)
         ent_res_fields = self.dataStore.getFields(ent_res, src)
-        entities = [d.get["name_kwd"] for d in ent_res_fields.values() if d.get("name_kwd")]
+        entities = [d["name_kwd"] for d in ent_res_fields.values() if d.get("name_kwd")]
         ent_ids = self.dataStore.getChunkIds(ent_res)
         ent_content = merge_into_first(ent_res_fields, "-Entities-")
         if ent_content: