CKE5 validator false negative on wildcard elements ("the following elements are missing")

Problem/Motivation

When adding the "elements" to a CKE5 plugin definition, you might want to use a wildcard to, for example, whitelist a set of classes on all HTML elements:

my_plugin:
  ckeditor5:
    plugins: [ htmlSupport.GeneralHtmlSupport ]
    config:
      htmlSupport:
        allow:
          - name:
              regexp:
                pattern: /.*/
            classes: [my, whitelisted, classes]
  drupal:
    label: Whitelisted elements
    library: core/ckeditor5.htmlSupport
    elements:
      - <* class="my whitelisted classes">

This is a not so strange scenario: think for example about keeping backwards compatibility with CKE4 while retaining some control on the markup.

But this will fail constraint validation, as it seems the <*> wildcard has already other two attributes whitelisted (lang and dir) by Drupal core CKE5 plugins, and it looks like the validator is searching for a exact match and won't consider <* class="my whitelisted classes"> to be a valid subset of <* dir="ltr rtl" lang class="my whitelisted classes">:

The message:

The current CKEditor 5 build requires the following elements and attributes:
(...) <* dir="ltr rtl" lang class="my whitelisted classes"> (...)
The following elements are missing:
<* class="my whitelisted classes">

Steps to reproduce

- Create a format with Limit HTML allowed tags filter and CKE5
- Create a custom plugin that whitelists classes on all HTML elements by using the <* class="my class"> notation on the elements property.
- Try to save the format. It will fail as it won't pass constraint validation.

Proposed resolution

The validator should consider <* class="my whitelisted classes"> to be valid even if there are more attributes whitelisted on the same definition, i.e: <* dir="ltr rtl" lang class="my whitelisted classes">.

Remaining tasks

User interface changes

None

Introduced terminology

API changes

Data model changes

Release notes snippet