[Frontend] Remove librosa from audio dependency

[Isotr0py]

Purpose

Related issues:

• [Installation]: LGPL license in dependencies vllm-omni#1013
• License risk: Librosa, Sox and other audio processing libraries vllm-omni#1725
  Remove librosa from audio dependency, so downstream projects needs audio support like vllm-omni can avoid affected by LGPL.

Test Plan

pytest -s -v tests/multimodal/test_audio.py
pytest -s -v tests/multimodal/meida/test_audio.py

Test Result

All tests should pass

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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.

[gemini-code-assist]

Code Review

This pull request replaces the librosa dependency with pyav for audio processing, which is a good move to streamline dependencies. The changes are mostly correct and cover various parts of the codebase, including models, utilities, and tests. However, I've identified two critical issues. First, a new test for pyav resampling is incorrectly implemented and tests the wrong function. Second, the new load_audio_pyav function has a bug where it returns the original sample rate instead of the target sample rate after resampling, which could lead to significant issues in downstream processing. I've provided detailed comments and suggestions to address these critical problems.

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @Isotr0py.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[DarkLight1337]

See if the CI environments can install av correctly. We should also check the CPU smoke test on main after merging

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @Isotr0py.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @Isotr0py.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork