Ckeditor5: Restricting the style attribute in <span> tag has restricted some modules to work as expected.

Problem/Motivation

Ckeditor has introduced a very strict validations or element filtering process where attribute like style are not allowed due to security concerns.
Because of that modules like colorbutton has lost their compatibility.

Steps to reproduce

1. - Enable colorbutton module
2. - Enable the colorbutton in the editor formats
3. - Add a new content and add text and use colorbutton to highlight.
4. - Enable and switch to CKE5 and see the results.

Expected :
- All the inline styles added by color-button should work

Actual:
- All the inline styling are gone

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet