Misc: fix some typos (#14987)

### What problem does this PR solve?

Fix minor code quality issues:

1. Fix typo in assertion error message: "Can't fine" → "Can't find"
2. Remove duplicate line in common/connection_utils.py

### Type of change

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

api/db/services/document_service.py

@@ -709,7 +709,7 @@ class DocumentService(CommonService):
     def clear_chunk_num(cls, doc_id):
         """Deprecated: use delete_document_and_update_kb_counts instead."""
         doc = cls.model.get_by_id(doc_id)
-        assert doc, "Can't fine document in database."
+        assert doc, "Can't find document in database."
 
         num = (
             Knowledgebase.update(token_num=Knowledgebase.token_num - doc.token_num, chunk_num=Knowledgebase.chunk_num - doc.chunk_num, doc_num=Knowledgebase.doc_num - 1)
@@ -722,7 +722,7 @@ class DocumentService(CommonService):
     @DB.connection_context()
     def clear_chunk_num_when_rerun(cls, doc_id):
         doc = cls.model.get_by_id(doc_id)
-        assert doc, "Can't fine document in database."
+        assert doc, "Can't find document in database."
 
         num = (
             Knowledgebase.update(

common/connection_utils.py

@@ -115,7 +115,6 @@ async def construct_response(code=RetCode.SUCCESS, message="success", data=None,
     response.headers["Access-Control-Allow-Origin"] = "*"
     response.headers["Access-Control-Allow-Method"] = "*"
     response.headers["Access-Control-Allow-Headers"] = "*"
-    response.headers["Access-Control-Allow-Headers"] = "*"
     response.headers["Access-Control-Expose-Headers"] = "Authorization"
     return response
 
@@ -135,6 +134,5 @@ def sync_construct_response(code=RetCode.SUCCESS, message="success", data=None,
     response.headers["Access-Control-Allow-Origin"] = "*"
     response.headers["Access-Control-Allow-Method"] = "*"
     response.headers["Access-Control-Allow-Headers"] = "*"
-    response.headers["Access-Control-Allow-Headers"] = "*"
     response.headers["Access-Control-Expose-Headers"] = "Authorization"
     return response