build(deps): bump sphinx-toolbox from 4.1.1 to 4.1.2 in /requirements (#21494)

Bumps [sphinx-toolbox](https://github.com/sphinx-toolbox/sphinx-toolbox) from 4.1.1 to 4.1.2.
- [Release notes](https://github.com/sphinx-toolbox/sphinx-toolbox/releases)
- [Changelog](https://github.com/sphinx-toolbox/sphinx-toolbox/blob/master/doc-source/changelog.rst)
- [Commits](https://github.com/sphinx-toolbox/sphinx-toolbox/compare/v4.1.1...v4.1.2)

---
updated-dependencies:
- dependency-name: sphinx-toolbox
  dependency-version: 4.1.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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