Bump @ckeditor/ckeditor5-essentials from 11.0.5 to 15.0.0

Bumps [@ckeditor/ckeditor5-essentials](https://github.com/ckeditor/ckeditor5-essentials) from 11.0.5 to 15.0.0.
- [Release notes](https://github.com/ckeditor/ckeditor5-essentials/releases)
- [Changelog](https://github.com/ckeditor/ckeditor5-essentials/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ckeditor/ckeditor5-essentials/compare/v11.0.5...v15.0.0

)

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