Move some constants to common (#11004)

### What problem does this PR solve?

As title.

### Type of change

- [x] Refactoring

---------

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

graphrag/general/smoke.py

@@ -21,7 +21,7 @@ import networkx as nx
 import trio
 
 from api import settings
-from api.db import LLMType
+from common.constants import LLMType
 from api.db.services.document_service import DocumentService
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.db.services.llm_service import LLMBundle

graphrag/light/smoke.py

@@ -21,7 +21,7 @@ import networkx as nx
 import logging
 import trio
 
-from api.db import LLMType
+from common.constants import LLMType
 from api.db.services.document_service import DocumentService
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.db.services.llm_service import LLMBundle

graphrag/search.py

@@ -315,7 +315,7 @@ class KGSearch(Dealer):
 if __name__ == "__main__":
     from api import settings
     import argparse
-    from api.db import LLMType
+    from common.constants import LLMType
     from api.db.services.knowledgebase_service import KnowledgebaseService
     from api.db.services.llm_service import LLMBundle
     from api.db.services.user_service import TenantService