Bump react-router-dom from 6.26.2 to 6.28.0 in /app/frontend (Azure-Samples#2172)

Bumps [react-router-dom](https://github.com/remix-run/react-router/tree/HEAD/packages/react-router-dom) from 6.26.2 to 6.28.0.
- [Release notes](https://github.com/remix-run/react-router/releases)
- [Changelog](https://github.com/remix-run/react-router/blob/main/packages/react-router-dom/CHANGELOG.md)
- [Commits](https://github.com/remix-run/react-router/commits/[email protected]/packages/react-router-dom)

---
updated-dependencies:
- dependency-name: react-router-dom
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

app/frontend/package-lock.json

@@ -27,7 +27,7 @@
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-markdown": "^9.0.1",
-    "react-router-dom": "^6.26.2",
+    "react-router-dom": "^6.28.0",
     "react-helmet-async": "^2.0.5",
     "react-i18next": "^15.1.1",
     "react-syntax-highlighter": "^15.6.1",