Bump react-i18next from 15.1.1 to 15.4.1 in /app/frontend (#2376)

Bumps [react-i18next](https://github.com/i18next/react-i18next) from 15.1.1 to 15.4.1.
- [Changelog](https://github.com/i18next/react-i18next/blob/master/CHANGELOG.md)
- [Commits](i18next/react-i18next@v15.1.1...v15.4.1)

---
updated-dependencies:
- dependency-name: react-i18next
  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

@@ -29,7 +29,7 @@
     "react-markdown": "^9.0.1",
     "react-router-dom": "^6.28.0",
     "react-helmet-async": "^2.0.5",
-    "react-i18next": "^15.1.1",
+    "react-i18next": "^15.4.1",
     "react-syntax-highlighter": "^15.6.1",
     "rehype-raw": "^7.0.0",
     "remark-gfm": "^4.0.0",