Make metaschema-draft-07-unofficial-strict.json validate against itself

[Vampire]

Area with issue?

JSON Schema

✔️ Expected Behavior

As metaschema-draft-07-unofficial-strict.json enforces recommendations you state that schemas should follow.
But applying the schema to itself lights up the IDE like a christmas tree.
Would be nice if the meta schema would dogfood and be valid against itself. :-)

❌ Actual Behavior

It does not validate

YAML or JSON file that does not work.

No response

IDE or code editor.

None

Are you making a PR for this?

No, someone else must create the PR.

[Vampire]

With #4035 merged, this can be simply checked by executing

npm run check-strict -- --SchemaName=metaschema-draft-07-unofficial-strict.json

:-)