feat(YALB-1428): set default values for variables

Set defaults in case there ever is an instance where the array items do
not exist, allowing the method to progress gracefully.

web/profiles/custom/yalesites_profile/modules/custom/ys_core/ys_core.module

@@ -321,8 +321,8 @@ function ys_core_taxonomy_term_update() {
  * "Call-to-action text".
  */
 function ys_core_field_widget_complete_form_alter(&$field_widget_complete_form, FormStateInterface $form_state, $context) {
-  $widget = &$field_widget_complete_form['widget']['0'];
-  $is_field_link = $field_widget_complete_form['widget']['#field_name'] == "field_link";
+  $widget = &$field_widget_complete_form['widget']['0'] ?? NULL;
+  $is_field_link = ($field_widget_complete_form['widget']['#field_name'] ?? "") == "field_link";
 
   if (isset($widget) && $widget['#bundle'] == 'cta_banner' && $is_field_link) {
     $widget['title']['#title'] = t('Call-to-action text');