Build: Bump s3fs from 2026.4.0 to 2026.9.0

Bumps [s3fs](https://github.com/fsspec/s3fs) from 2026.4.0 to 2026.9.0.
- [Changelog](https://github.com/fsspec/s3fs/blob/main/release-procedure.md)
- [Commits](fsspec/s3fs@2026.4.0...2026.9.0)

---
updated-dependencies:
- dependency-name: s3fs
  dependency-version: 2026.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]