Notify 'authenticated user' role is not working

Problem/Motivation

The configuration option to notify users by role doesn't work for the 'authenticated user' role. This because users can't be fetched with the current lookup implementation as the 'authenticated user' role is an implicit role:

// Roles.
foreach ($notification->getRoleIds() as $role) {
  /** @var \Drupal\user\UserInterface[] $role_users */
  $role_users = $this->entityTypeManager
    ->getStorage('user')
    ->loadByProperties(['roles' => $role]);
  foreach ($role_users as $role_user) {
    $data['to'][] = $role_user->getEmail();
  }
}

Proposed resolution

Either discard the option in the configuration form or alter the lookup to query the authenticated users as recipients.