fix(测试跟踪): 脑图将相邻的临时节点批量修改为用例，保存报错

--bug=1014159 --user=陈建星 【测试跟踪】功能用例脑图模式，模块下批量修改下级主题为用例，有报错 https://www.tapd.cn/55049933/s/1183897

frontend/src/business/components/track/common/minder/TestCaseMinder.vue

@@ -483,7 +483,7 @@ name: "TestCaseMinder",
             } else {
               testCase.moveMode = 'APPEND';
             }
-          } else if (this.isCaseNode(nextNode)) {
+          } else if (this.isCaseNode(nextNode) && !nextNode.data.isExtraNode) {
             let nextId = nextNode.data.id;
             if (nextId && nextId.length > 15) {
               testCase.targetId = nextId;