Change MimeTypeGuesser to core/lib/Drupal/Core/File/MimeType/MimeTypeGuesser.php

Problem/Motivation

The MimeTypeGuesser Drupal\Core\ProxyClass\File\MimeType\MimeTypeGuesser was deleted in #3579673: Remove lazy declaration and proxy class for MIME type guessers and will be removed from 11.4.0. This needs to be updated to Drupal\Core\File\MimeType\MimeTypeGuesser.

I discovered this problem in another contrib module and did a search for others using the same pattern.

Proposed resolution

Update Drupal\Core\ProxyClass\File\MimeType\MimeTypeGuesser to Drupal\Core\File\MimeType\MimeTypeGuesser in EmailAttachmentEvaluator.

Remaining tasks

User interface changes

API changes

Data model changes