Fix bugs (#3502)

### What problem does this PR solve?

1. Remove unused code
2. Fix type mismatch, in nlp search and infinity search interface
3. Fix chunk list, get all chunks of this user.

### Type of change

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

---------

Signed-off-by: jinhai <haijin.chn@gmail.com>

graphrag/search.py

@@ -23,7 +23,7 @@ from rag.nlp.search import Dealer
 
 
 class KGSearch(Dealer):
-    def search(self, req, idxnm, kb_ids, emb_mdl, highlight=False):
+    def search(self, req, idxnm: str | list[str], kb_ids: list[str], emb_mdl=None, highlight=False):
         def merge_into_first(sres, title="") -> dict[str, str]:
             if not sres:
                 return {}