Bump guzzlehttp/psr7 from 2.10.2 to 2.12.1 in /legacy_hook

Bumps [guzzlehttp/psr7](https://github.com/guzzle/psr7) from 2.10.2 to 2.12.1.
- [Release notes](https://github.com/guzzle/psr7/releases)
- [Changelog](https://github.com/guzzle/psr7/blob/3.0/CHANGELOG.md)
- [Commits](guzzle/psr7@2.10.2...2.12.1)

---
updated-dependencies:
- dependency-name: guzzlehttp/psr7
  dependency-version: 2.12.1
  dependency-type: direct:production
...

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Author: dependabot[bot]