[META] Update schema's with multiple contraints to SequentiallyConstraint

Problem/Motivation

In ✨ Add support for Sequentially constraint Active we introduced the SequentiallyConstraint. This is usefull to communicate errors in a more usefull fasion. So for example:

    # file: block.schema.yml
    theme:
      type: string
      label: 'Theme'
      constraints:
        NotBlank: []
        ExtensionName: []
        ExtensionExists: theme

Here it could first say "Should not be blank", then if that is valid "Invalid extension name", then "Extension does not exist". Instead of just printing all of those.

Steps to reproduce

Proposed resolution

Go through all contraints that consist of multiple contraints and update those to SequentiallyConstraint where is makes sense. Let's do that in child issues.

• block.block.*.mapping.theme
• block.block.*.mapping.region
• ckeditor5.plugin.ckeditor5_language .mappoing.language_list
• ...

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet