Google Analytics script execution should be deferred

Currently GA script executes asynchronously while page is loading without a good reason for doing so since there are no custom GA events being tracked when page load is happening or right after it finishes, it's also showing up in Lighthouse score report as a very small main-thread blocker. Performance-wise it would be better to defer the script execution until the page has finished loading

先找出頁面載入期間使用的 Google Analytics 整合。確認其目前的非同步行為，接著驗證指令碼是否延遲到頁面載入完成後才執行，並確認 Lighthouse 不再將其回報為主執行緒阻塞項目。