fix(测试跟踪): 评审脑图用例下添加子节点，保存后会添加一条空评论

--bug=1033825 --user=陈建星 [测试跟踪] github #28040在脑图模式下评审用例，添加的详细信息没有记录到评审记录中 https://www.tapd.cn/55049933/s/1448169

test-track/frontend/src/business/case/components/TestCaseEditOtherInfo.vue

@@ -275,7 +275,7 @@ export default {
       testCaseCommentList(id)
         .then(res => {
           this.result.loading = false;
-          this.comments = res.data;
+          this.comments = res.data.filter(comment => comment.description);
         });
     },
     setRelationshipCount(count) {