Bump next from 14.2.5 to 14.2.15 in /zbook_frontend (#57)

Bumps [next](https://github.com/vercel/next.js) from 14.2.5 to 14.2.15.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.2.5...v14.2.15)

---
updated-dependencies:
- dependency-name: next
  dependency-type: direct:production
...

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

zbook_frontend/package.json

@@ -25,7 +25,7 @@
     "html-react-parser": "^4.2.10",
     "jsdom": "^24.0.0",
     "mermaid": "^10.9.0",
-    "next": "14.2.5",
+    "next": "14.2.15",
     "next-auth": "^5.0.0-beta.19",
     "next-intl": "^3.15.3",
     "next-themes": "^0.3.0",