Bump torchaudio from 2.8.0 to 2.9.0

Bumps [torchaudio](https://github.com/pytorch/audio) from 2.8.0 to 2.9.0.
- [Release notes](https://github.com/pytorch/audio/releases)
- [Commits](pytorch/audio@v2.8.0...v2.9.0)

---
updated-dependencies:
- dependency-name: torchaudio
  dependency-version: 2.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements_test.txt

@@ -29,7 +29,7 @@ keras==3.11.3
 
 # PyTorch
 torch==2.8.0
-torchaudio==2.8.0
+torchaudio==2.9.1
 torchvision==0.23.0
 
 # PyTorch image transformers