chore(deps)(deps): bump @angular/material in /frontend (#46)

Bumps [@angular/material](https://github.com/angular/components) from 20.2.12 to 20.2.13.
- [Release notes](https://github.com/angular/components/releases)
- [Changelog](https://github.com/angular/components/blob/main/CHANGELOG.md)
- [Commits](angular/components@20.2.12...20.2.13)

---
updated-dependencies:
- dependency-name: "@angular/material"
  dependency-version: 20.2.13
  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>

Author: dependabot[bot]

frontend/package-lock.json

@@ -35,7 +35,7 @@
     "@angular/compiler": "^20.3.12",
     "@angular/core": "^20.3.10",
     "@angular/forms": "^20.3.10",
-    "@angular/material": "^20.2.12",
+    "@angular/material": "^20.2.13",
     "@angular/platform-browser": "^20.3.10",
     "@angular/router": "^20.3.10",
     "@apollo/client": "^4.0.9",