Problem/Motivation
Drupal\ckeditor5\SmartDefaultSettings::addToolbarItemsToMatchHtmlAttributesInFormat isn't necessarily handling use cases where CKEditor plugin only supports specific attribute value in the best possible way. Currently it will enable plugins that allow ALL values for an attribute. This means the attribute+value is now allowed but additional attribute values are permitted as well. This may need to be more selective.
If we don't do that, we could end up allowing <p class> instead of only allowing <p class="text-align-center">, for example.