fix(性能测试): 修复查看报告监控的时候表格数据存在缓存的问题

--bug=1022432 --user=刘瑞斌 【性能测试】github#21548，性能测试报告监控资源切换，表格数据不切换 https://www.tapd.cn/55049933/s/1335014

Closes #21548

performance-test/frontend/src/business/report/components/MonitorCard.vue

@@ -174,6 +174,7 @@ export default {
   },
   methods: {
     getResource(currentInstance) {
+      this.tableData = [];
       // this.init = true;
       if (this.planReportTemplate) {
         this.instances = this.planReportTemplate.reportResource;