fix:ai问答topic编辑

controllers/ai/ai.go

@@ -322,7 +322,7 @@ func (this *AiController) TopicEdit() {
 		br.ErrMsg = "获取数据失败！Err:" + err.Error()
 		return
 	}
-	if topic != nil && topic.AiChatTopicId != req.AiChatTopicId {
+	if topic != nil && topic.AiChatTopicId > 0 && topic.AiChatTopicId != req.AiChatTopicId {
 		br.Msg = "话题名称已存在，请重新修改！"
 		return
 	}