chore(library): remove unused vllm requirements.txt files

[Pouyanpi]

Summary

Removes unused requirements.txt files from patronusai and llama_guard library directories that pinned vllm==0.10.1.1 (which has known security vulnerabilities).

we won't get any of these in future:

https://github.com/NVIDIA-NeMo/Guardrails/security/dependabot/130
https://github.com/NVIDIA-NeMo/Guardrails/security/dependabot/129
https://github.com/NVIDIA-NeMo/Guardrails/security/dependabot/125
https://github.com/NVIDIA-NeMo/Guardrails/security/dependabot/124

Context

• These requirements.txt files were not referenced or used by any code in the codebase
• The Python code in both libraries does not import vllm
• vllm is only needed for users who choose to self-host the models, which is already documented in the deployment guides
• Removing these files eliminates the pinned vulnerable vllm version from the repository

[greptile-apps]

_{2 files reviewed, no comments}

_{Edit Code Review Agent Settings | Greptile}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[tgasser-nv]

Looks good, will be great to get rid of the spurious vllm vulnerability messages