Bump next from 14.2.25 to 15.3.2 in /frontend

Bumps [next](https://github.com/vercel/next.js) from 14.2.25 to 15.3.2.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.2.25...v15.3.2)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.3.2
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

frontend/package-lock.json

@@ -23,7 +23,7 @@
     "eslint-config-next": "14.2.15",
     "framer-motion": "^11.11.7",
     "intl-messageformat": "^10.5.14",
-    "next": "^14.2.25",
+    "next": "^15.3.2",
     "next-themes": "^0.2.1",
     "postcss": "8.4.47",
     "react": "18.3.1",