Add support for Ckeditor 5

I created a patch which includes this change and can be applied with composer to version 8.x-1.6. The change allowed me to convert my text format to ckeditor 5. I'm including it here in case anyone needs it while we wait for this to be merged into a new release.

@briantbailey you can always use any MR as a patch by adding .patch at the end of the link

For example https://git.drupalcode.org/project/elf/-/merge_requests/8 -> https://git.drupalcode.org/project/elf/-/merge_requests/8.patch