External link causes failure if no title provided, with Drupal 11

Problem/Motivation

When using a Link component on an external URL without specifying the 'title' attribute, the rendering crashes when on a Drupal 11 site :
TypeError: Drupal\Component\Utility\Html::escape(): Argument #1 ($text) must be of type string, null given, called in /var/www/html/web/core/lib/Drupal/Component/Render/FormattableMarkup.php on line 238 in Drupal\Component\Utility\Html::escape() (line 433 of core/lib/Drupal/Component/Utility/Html.php).

Steps to reproduce

Using the render API, insert a Link component :

$build['a-link'] = [
  '#type' => 'component',
  '#component' => 'ui_suite_dsfr:link',
  '#slots' => [
    'label'=> 'Wikipedia',
  ],
  '#props' => [
    'external' => TRUE,
    'url' => Url::fromUri('https://fr.wikipedia.org'),
  ],
];

The problem is avoided by specifying an empty string for the 'title' prop:

$build['a-link'] = [
  '#type' => 'component',
  '#component' => 'ui_suite_dsfr:link',
  '#slots' => [
    'label'=> 'Wikipedia',
  ],
  '#props' => [
    'external' => TRUE,
    'url' => Url::fromUri('https://fr.wikipedia.org'),
    'title' => '',
  ],
];

Proposed resolution

The problem occurs when concataining ' - new window' to the title, using a TranslatableMarkup.
TranslatableMarkup does not allow null values anymore for placeholders. The value of the title attribute should be coerced to an empty string when null, or the case should be treated separately.

Attached is a proposed resolution, that also addresses another issue : 'new window' is not translated.

Remaining tasks

User interface changes

API changes

Data model changes