[framework-fixtures]: Bump astro

Bumps the core group with 1 update in the /packages/static-build/test/fixtures/astro-v4 directory: [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro).


Updates `astro` from 4.7.0 to 4.9.1
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/astro/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/astro@4.9.1/packages/astro)

---
updated-dependencies:
- dependency-name: astro
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: core
...

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