ci: update azure-pipelines schema

[Borda]

Before submitting

• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did all existing and newly added tests pass locally?

What does this PR do?

need to be tested/validated on https://github.com/Lightning-AI/lightning-thunder/tree/main/.azure
trying to address

.azure/gpu-tests.yml
Error: schemafile was not valid

SchemaError: '^[^\\/~\\^\\: \\[\\]\\\\]+(\\/[^\\/~\\^\\: \\[\\]\\\\]+)*$' is not a 'regex'

Failed validating 'format' in metaschema['properties']['definitions']['additionalProperties']['properties']['pattern']:
    {'type': 'string', 'format': 'regex'}

On schema['definitions']['branchFilter']['pattern']:
    '^[^\\/~\\^\\: \\[\\]\\\\]+(\\/[^\\/~\\^\\: \\[\\]\\\\]+)*$'
  in "/opt/hostedtoolcache/Python/3.12.8/x64/lib/python3.12/site-packages/check_jsonschema/checker.py", line 56
  >>> return self._schema_loader.get_validator(

PR review

Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in GitHub issues there's a high chance it will not be merged.

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📚 Documentation preview 📚: https://lit-utilities--355.org.readthedocs.build/en/355/