chore(deps): bump next in /packages/themes/examples/preview (#20878)

Bumps [next](https://github.com/vercel/next.js) from 15.3.4 to 15.4.7.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.3.4...v15.4.7)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.4.7
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Riddhi Bansal <41935566+riddhybansal@users.noreply.github.com>

Author: dependabot[bot]

packages/themes/examples/preview/package.json

@@ -8,7 +8,7 @@
   "dependencies": {
     "@carbon/colors": "link:../../../colors",
     "@carbon/themes": "link:../../",
-    "next": "^15.3.3",
+    "next": "^15.4.7",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
     "sass": "^1.36.0"