Bump @angular/material from 16.2.7 to 16.2.9 in /frontend (#189)

Bumps [@angular/material](https://github.com/angular/components) from 16.2.7 to 16.2.9.
- [Release notes](https://github.com/angular/components/releases)
- [Changelog](https://github.com/angular/components/blob/main/CHANGELOG.md)
- [Commits](https://github.com/angular/components/compare/16.2.7...16.2.9)

---
updated-dependencies:
- dependency-name: "@angular/material"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

frontend/package.json

@@ -16,7 +16,7 @@
     "@angular/compiler": "^16.2.10",
     "@angular/core": "^16.2.8",
     "@angular/forms": "^16.2.8",
-    "@angular/material": "^16.2.7",
+    "@angular/material": "^16.2.9",
     "@angular/platform-browser": "^16.2.10",
     "@angular/platform-browser-dynamic": "^16.2.8",
     "@angular/router": "^16.2.8",