Autofill media name if mapped in the media source

Added a check if the mapping has been added in the media type, copied from Lendude's solution in https://www.drupal.org/project/drupal/issues/3185321#comment-14349402 →

Thank you for your suggestion.

I think we can pre-release this core-feature in this module.

This seems to work as expected.

Steps:

1. Apply the patch
2. Add new media (I used image), file name was prefilled as I have the mapping set (default in Drupal install)
3. Change the name mapping value to Skip, and expose the name field (it is still pre-filled if the name field is not exposed on the form)
4. Upload a new image, field is empty.