ISTWCMS-6945: fix getting the form id for label on details elements

uw_fdsu_theme_resp.theme

@@ -740,5 +740,8 @@ function uw_fdsu_theme_resp_preprocess_details(&$variables) {
     if (isset($variables['element'][0]['#attributes']['data-drupal-selector'])) {
       $variables['form_field_id'] = $variables['element'][0]['#attributes']['data-drupal-selector'];
     }
+    else if (isset($variables['element']['#attributes']['data-drupal-selector'])) {
+      $variables['form_field_id'] = $variables['element']['#attributes']['data-drupal-selector'];
+    }
   }
 }