ISTWCMS-4532 Add services to remove 'This must be an external URL such as...

ISTWCMS-4532 Add services to remove 'This must be an external URL such as http://example.com' from the link field

src/EventSubscriber/UwEventEventSubscriber.php

+<?php
+
+namespace Drupal\uw_ct_event\EventSubscriber;
+
+use Drupal\field_event_dispatcher\Event\Field\WidgetFormAlterEvent;
+use Drupal\hook_event_dispatcher\HookEventDispatcherInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Class UwEventEventSubscriber.
+ *
+ * UW event event subscriber.
+ *
+ * @package Drupal\uw_ct_event\EventSubscriber
+ */
+class UwEventEventSubscriber implements EventSubscriberInterface {
+
+  /**
+   * Alter widget form.
+   *
+   * Remove 'This must be an external URL such as http://example.com' from the
+   * link field.
+   *
+   * @param \Drupal\field_event_dispatcher\Event\Field\WidgetFormAlterEvent $event
+   *   The event.
+   */
+  public function alterWidgetForm(WidgetFormAlterEvent $event): void {
+    $element = &$event->getElement();
+    // Only modify element 'Map' (field_uw_event_map).
+    if (isset($element['#title']) && $element['#title'] == "Map") {
+      $context = $event->getContext();
+      // When creating or editing an event node,
+      // remove 'This must be an external URL such as
+      // http://example.com' from the link field.
+      $forms = [
+        'node-uw-ct-event-form',
+        'node-uw-ct-event-edit-form',
+      ];
+      if (in_array($context['form']['#attributes']['class'][0], $forms)) {
+        unset($element['uri']['#description']['#items'][1]);
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    return [
+      HookEventDispatcherInterface::WIDGET_FORM_ALTER => 'alterWidgetForm',
+    ];
+  }
+
+}

uw_ct_event.services.yml

+services:
+  uw_ct_event.event_subscriber:
+    class: '\Drupal\uw_ct_event\EventSubscriber\UwEventEventSubscriber'
+    tags:
+      - { name: 'event_subscriber' }