fix delete message error (#2153)

### What problem does this PR solve?



### Type of change

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

api/apps/conversation_app.py

@@ -227,7 +227,7 @@ def delete_msg():
         assert conv["message"][i+1]["id"] == req["message_id"]
         conv["message"].pop(i)
         conv["message"].pop(i)
-        conv["reference"].pop(i)
+        conv["reference"].pop(max(0, i//2-1))
         break
 
     ConversationService.update_by_id(conv["id"], conv)

api/db/services/task_service.py

@@ -42,6 +42,7 @@ class TaskService(CommonService):
             cls.model.doc_id,
             cls.model.from_page,
             cls.model.to_page,
+            cls.model.retry_count,
             Document.kb_id,
             Document.parser_id,
             Document.parser_config,