refactor: Expose Metal device buffer limits

[MaximKotliar]

Makes max_ops_per_buffer and max_mb_per_buffer public members of the Metal Device class. This allows direct access to these command buffer configuration parameters.

Proposed changes

Please include a description of the problem or feature this PR is addressing. If there is a corresponding issue, include the issue #.

Checklist

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• I have read the CONTRIBUTING document
• I have run pre-commit run --all-files to format my code / installed pre-commit prior to committing changes
• I have added tests that prove my fix is effective or that my feature works
• I have updated the necessary documentation (if needed)

[awni]

Not sure of the purpose here.. closing for now. If you have a good reason to expose these let us know.

[MaximKotliar]

Sorry, i thought it was in draft. Will re-open with details.