ISTWCMS-4707: Not adding GA code to admin and default 403/404 pages.

uw_cfg_common.module

@@ -349,8 +349,28 @@ function uw_cfg_common_page_attachments(array &$page) {
     $page['#attached']['html_head'][] = [$data, 'uw-google-site-verification'];
   }
 
+  // Check if requested route is admin route. This should cover /node/1/edit,
+  // node/1/revisions, term/1/edit, webform results page
+  $skip_ga_snippet = \Drupal::service('router.admin_context')->isAdminRoute();
+
+  // When current route is not detected as admin path, check if route is
+  // 403 or 404. Skip injecting GA code snippets on those pages.
+  if (!$skip_ga_snippet) {
+    $route_name = \Drupal::routeMatch()->getRouteName();
+
+    // Check for default 403/404 pages. This will not cover any custom 403/404
+    // pages that may be webpages (e.g. /node/3).
+    if (in_array($route_name, ['system.403', 'system.404'])) {
+      $skip_ga_snippet = TRUE;
+    }
+    // Adding exception for layout builder.
+    elseif (preg_match('/^layout_builder\..+$/', $route_name)) {
+      $skip_ga_snippet = TRUE;
+    }
+  }
+
   // Get the code from config and inject to the page.
-  if (!empty($config->get('uw_cfg_common_ga_account'))) {
+  if (!$skip_ga_snippet && !empty($config->get('uw_cfg_common_ga_account'))) {
     $code = Html::escape($config->get('uw_cfg_common_ga_account'));
 
     $firstLetter = strtolower(substr($code, 0, 1));