Issue #3333841: Drupal Coding Standards Issues | phpcs

Great move, thank you.

This is just missing the service dependency injection per https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21StringTranslation%21StringTranslationTrait.php/trait/StringTranslationTrait/ :

If the class is capable of injecting services from the container, it should inject the 'string_translation' service and assign it to $this->stringTranslation.