fix(项目管理): 修复开启tcpMock时没有自动分配端口号的问题

--bug=1017940 --user=宋天阳 【项目设置】应用管理-接口测试，开启tcp mock端口没有自动选择可用端口
https://www.tapd.cn/55049933/s/1260516

project-management/frontend/src/business/menu/appmanage/AppManage.vue

@@ -392,7 +392,7 @@ export default {
     tcpMockSwitchChange(value, other) {
       if (value && this.config.mockTcpPort === 0) {
         genTcpMockPort(this.projectId).then(res => {
-          let port = res.data.data;
+          let port = res.data;
           this.config.mockTcpPort = port;
           this.$nextTick(() => {
             this.switchChange("MOCK_TCP_OPEN", value, ['MOCK_TCP_PORT', this.config.mockTcpPort]);