Add taxonomy translation route to _thunder_admin_enable_sidebar_tray()

Hello and thank you for a great theme :)

This is hardly a bug because it doesn't affect functionality in negative ways, but I recently noticed that the sidebar tray is missing some styles on taxonomy content_translation_add routes (see screenshot). The specific route check is performed in .theme by _thunder_admin_enable_sidebar_tray and contains the following switch case:

switch ($route->getRouteName()) {
    case 'entity.taxonomy_term.add_form':
    case 'node.add':
    case 'entity.node.content_translation_add':
      $result = TRUE;
  }

Fix

Adding 'entity.taxonomy_term.content_translation_add' to this list resolves the issue.