Issue #3427005: Add hide header option to extra settings.

Closes #3427005

src/Plugin/ViewsReferenceSetting/ViewsReferenceHeader.php

+<?php
+
+namespace Drupal\viewsreference\Plugin\ViewsReferenceSetting;
+
+use Drupal\Component\Plugin\PluginBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\views\ViewExecutable;
+use Drupal\viewsreference\Plugin\ViewsReferenceSettingInterface;
+
+/**
+ * The views reference setting header plugin.
+ *
+ * @ViewsReferenceSetting(
+ *   id = "header",
+ *   label = @Translation("Hide header"),
+ *   default_value = false,
+ * )
+ */
+class ViewsReferenceHeader extends PluginBase implements ViewsReferenceSettingInterface {
+
+  use StringTranslationTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function alterFormField(array &$form_field) {
+    $form_field['#type'] = 'checkbox';
+    $form_field['#weight'] = 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function alterView(ViewExecutable $view, $value) {
+    if (!empty($value) && !empty($view->display_handler->getOption('header'))) {
+      $view->display_handler->setOption('header', []);
+    }
+  }
+
+}