fix(schemas): autofix linting issues of biomaterial_core.json

[Karan-Palan]

Fixes #1626

Release notes

For biomaterial_core.json schema:

• Fixed issues with unknown keywords that don't have an x- prefix to ensure compatibility with future versions of JSON Schema.
• Resolved $ref sibling keyword evaluation issue in Draft 7 and older dialects.

Before and after:

Reviews requested

• Need 1-2 Reviewers to approve because this is a minor update.

Note

For context, I, along with Juan (JSON Schema TSC member) are defining linting rules for JSON Schema as a Part of a GSoC (Google Summer of code) project here - https://github.com/Karan-Palan/JSON-Schema-Linting, and implementing their auto-fixes here - https://github.com/sourcemeta/jsonschema/blob/main/docs/lint.markdown. We have recently added many rules prefixing unknown keywords with x- which will be introduced in the newer JSON Schema drafts
If beneficial to the project, I suggest integrating the complete cli with it to write the best schemas and catch any errors and follow best practices. Example of an integration - https://github.com/krakend/krakend-schema/blob/main/.github/workflows/validate-json-schema.yml#L10

[Karan-Palan]

Awaiting review @arschat @NoopDog