build: bump @fluentui/react from 8.121.4 to 8.121.7 in /code/frontend

Bumps [@fluentui/react](https://github.com/microsoft/fluentui) from 8.121.4 to 8.121.7.
- [Release notes](https://github.com/microsoft/fluentui/releases)
- [Changelog](https://github.com/microsoft/fluentui/blob/master/azure-pipelines.release.yml)
- [Commits](https://github.com/microsoft/fluentui/compare/@fluentui/react_v8.121.4...@fluentui/react_v8.121.7)

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

Signed-off-by: dependabot[bot] <[email protected]>

code/frontend/package.json

@@ -11,7 +11,7 @@
     },
     "dependencies": {
         "@babel/traverse": "^7.25.7",
-        "@fluentui/react": "^8.121.4",
+        "@fluentui/react": "^8.121.7",
         "@fluentui/react-icons": "^2.0.259",
         "@fortawesome/fontawesome-svg-core": "^6.6.0",
         "@fortawesome/free-solid-svg-icons": "^6.6.0",