chore(deps): update transformers requirement from >=5.8.1 to >=5.9.0 in /backend/python/transformers (#10005)

chore(deps): update transformers requirement

Updates the requirements on [transformers](https://github.com/huggingface/transformers) to permit the latest version.
- [Release notes](https://github.com/huggingface/transformers/releases)
- [Commits](https://github.com/huggingface/transformers/compare/v5.8.1...v5.9.0)

---
updated-dependencies:
- dependency-name: transformers
  dependency-version: 5.9.0
  dependency-type: direct:production
...

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