When adding a media item via the modal, display form errors inline within the modal

I don't have the option to edit an existing media item from the media widget. I'm wondering if you have installed a module or applied a patch that is adding the edit link?

Had the same issue on Drupal 10.3 when the user did not select any items and hit the submit button on the modal. The form state error messages were rendered behind the modal, so the user would have to close the modal first to be able to read the errors.

Even with the modal having a #media-library-messages element, that was not used when the errors were handled in the $form_state object.
Other issue with the container mentioned above was that on smaller screens it appeared above the rendered views, not on the modal top. The autofocus on the media add form still prevented users from getting the error message in a visible area.

In the attached solution, these are the modifications made:
1. Relocated the render array of #media-library-messages to the media library's AddFormBase.php to display them right after the form with autofocus.
2. Added an extra check for the modal form's Ajax callback to check if the form had any errors and update the response accordingly with a MessageCommand to display errors in the modal.
3. Removed all the errors from the Drupal::messenger() to avoid displaying duplicated messages when the modal is closed.

This solution might require some improvements but it could be a good starting point.

Thanks for working on this

So fixes should be placed in MRs vs patches as tests don't run.

Also will need some test coverage

Thanks!