perf: links to cross-origin destinations are unsafe

Add `ref=noopener` to the `a.goog-logo-link` tag to solve the issue
found out by Chrome lighthouse.

_includes/extensions/google-translate.html

@@ -29,6 +29,12 @@ function googleTranslateElementInit() {
     layout: google.translate.TranslateElement.InlineLayout.VERTICAL
   }, 'google_translate_element');
 
+  // Links to cross-origin destinations are unsafe
+  var gll = document.getElementsByClassName('goog-logo-link')[0];
+  if (gll) {
+    gll.setAttribute('rel', 'noopener');
+  }
+
   function restoreLang() {
     var iframe = document.getElementsByClassName('goog-te-banner-frame')[0];
     if (!iframe) return;