[KVConnector] remove unused code (the model aware kv ops class)

[KuntaiDu]

The model_aware_kv_ops_helper is not being used in vLLM and can be safely deleted.

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.
• (Optional) Release notes update. If your change is user facing, please update the release notes draft in the Google Doc.

[chatgpt-codex-connector]

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[gemini-code-assist]

Code Review

This pull request removes the model_aware_kv_ops_helper class from vllm/distributed/kv_transfer/kv_connector/utils.py. The description states this class is unused. After reviewing the provided files, I can confirm that there are no references to model_aware_kv_ops_helper, supporting the claim that it is dead code. The removal is a positive change for code maintainability. The change is straightforward and I have not identified any issues.

[markmc]

Added by #16020 and usage removed by #21785, lgtm

Just need to fix pre-commit