Resolve #3490037 "Min drupal 10.3"

Closes #3490037

src/Attribute/PrivateMessageConfigForm.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\private_message\Attribute;
+
+use Drupal\Component\Plugin\Attribute\Plugin;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+
+/**
+ * The private message configuration form plugin attribute.
+ */
+#[\Attribute(\Attribute::TARGET_CLASS)]
+class PrivateMessageConfigForm extends Plugin {
+
+  /**
+   * Constructs a PrivateMessageConfigForm attribute.
+   *
+   * @param string $id
+   *   The plugin ID.
+   * @param \Drupal\Core\StringTranslation\TranslatableMarkup $name
+   *   The name of the form plugin.
+   */
+  public function __construct(
+    public readonly string $id,
+    public readonly TranslatableMarkup $name,
+  ) {}
+
+}