Make it compatible with D10.3 experimental core Navigation ad Navigation Top Bar modules

BTW I fixed this in a custom module where I make other improvements and changes to the Navigation and Navigation Top Bar.

/**
 * Implements hook_preprocess_HOOK().
 *
 * Make general changes to the Navigation Top Bar.
 */
function mymodule_preprocess_top_bar(array &$variables): void {

  // Add geysir to the top bar from core's navigation_top_bar module.
  if (\Drupal::service('module_handler')->moduleExists('geysir')) {
    $variables['local_tasks']['#local_tasks']['geysir'] = [
      '#theme' => 'top_bar_local_task',
      '#link' => [
        '#type' => 'html_tag',
        '#tag' => 'button',
        'child' => [
          'icon' => [
            '#type' => 'html_tag',
            '#tag' => 'span',
            '#attributes' => [
              'class' => ['geysir-icon'],
            ],
          ],
          'text' => ['#plain_text' => t('Geysir')]
        ],
        '#attributes' => [
          'class' => ['toolbar-icon-geysir'],
          'aria-pressed' => 'false',
          'type' => 'button',
        ],
        '#attached' => [
          'library' => [
            'geysir/geysir-toolbar',
          ],
        ],
      ],
    ];
  }
}

And in CSS:

.toolbar-icon-geysir{
    border: none;
    background: inherit;
    width: 100%;
    text-align: left;
}

.geysir-icon:before {
    content: '☐';
}
.geysir-icon {
    display: inline-block;
}