Flushing image, when webp module is used, does work correctly

The combination of these 2 tickets causes issues:

• https://www.drupal.org/project/flush_single_image/issues/3187232 →
• https://www.drupal.org/project/flush_single_image/issues/3102639 →

When the webp image exists, it will only delete that one causing images but the be updated correcly.
If you choose regeneration, the derivative is forced saved as the webp variation.