fix(测试计划): 模块树未加载数据#1006453

--bug=1006453 --user=lyh 【github#5998】测试计划中第二次关联测试计划，左边的测试模块不展示了
https://www.tapd.cn/55049933/s/1044941

frontend/src/business/components/track/plan/view/comonents/functional/TestCaseFunctionalRelevance.vue

@@ -166,6 +166,9 @@ export default {
       if (this.$refs.table) {
         this.$refs.table.clear();
       }
+      if (this.projectId) {
+        this.getProjectNode(this.projectId);
+      }
     },
     setProject(projectId) {
       this.projectId = projectId;