Drupal-specific CKEditor 5 plugins should be able to use Drupal's JS translation API: Drupal.t()

Problem/Motivation

Sibling of #3228464: [upstream] API for contrib projects to load CKEditor translations.

See https://git.drupalcode.org/project/ckeditor5/-/merge_requests/56#note_39145.

This will need tests similar to \Drupal\Tests\ckeditor\Kernel\CKEditorTest::testJSTranslation() for CKEditor 4 in core.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes