build(deps): bump mkdocs-material in /hack/mkdocs/image (#3699)

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.6.8 to 9.6.9.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.6.8...9.6.9)

---
updated-dependencies:
- dependency-name: mkdocs-material
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

hack/mkdocs/image/requirements.txt

@@ -10,7 +10,7 @@ MarkupSafe==3.0.2
 mkdocs==1.6.1
 mkdocs-awesome-pages-plugin==2.10.1
 mkdocs-macros-plugin==1.3.7
-mkdocs-material==9.6.8
+mkdocs-material==9.6.9
 mkdocs-redirects==1.2.2
 mkdocs-mermaid2-plugin==1.2.1
 pandas>=2.0.3