Bump werkzeug from 3.1.5 to 3.1.6 in /sandbox

Bumps [werkzeug](https://github.com/pallets/werkzeug) from 3.1.5 to 3.1.6.
- [Release notes](https://github.com/pallets/werkzeug/releases)
- [Changelog](https://github.com/pallets/werkzeug/blob/main/CHANGES.rst)
- [Commits](pallets/werkzeug@3.1.5...3.1.6)

---
updated-dependencies:
- dependency-name: werkzeug
  dependency-version: 3.1.6
  dependency-type: indirect
...

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Author: dependabot[bot]