clean console apis and rag cleans. (#25042)

Signed-off-by: zhanluxianshen <zhanluxianshen@163.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/controllers/console/explore/conversation.py

             ConversationService.delete(app_model, conversation_id, current_user)
         except ConversationNotExistsError:
             raise NotFound("Conversation Not Exists.")
-        WebConversationService.unpin(app_model, conversation_id, current_user)
 
         return {"result": "success"}, 204
 

api/controllers/web/conversation.py

             ConversationService.delete(app_model, conversation_id, end_user)
         except ConversationNotExistsError:
             raise NotFound("Conversation Not Exists.")
-        WebConversationService.unpin(app_model, conversation_id, end_user)
-
         return {"result": "success"}, 204
 
 

api/core/rag/extractor/blob/blob.py

             Blob instance
         """
         if mime_type is None and guess_type:
-            _mimetype = mimetypes.guess_type(path)[0] if guess_type else None
+            _mimetype = mimetypes.guess_type(path)[0]
         else:
             _mimetype = mime_type
         # We do not load the data immediately, instead we treat the blob as a