Bump next from 14.2.10 to 15.5.18 in /examples/pre/nextjs

Bumps [next](https://github.com/vercel/next.js) from 14.2.10 to 15.5.18.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.2.10...v15.5.18)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.5.18
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

examples/pre/nextjs/package.json

@@ -17,7 +17,7 @@
     "eslint": "8.57.0",
     "eslint-config-next": "14.0.4",
     "ethers": "^5.8.0",
-    "next": "14.2.10",
+    "next": "15.5.18",
     "react": "18.3.1",
     "react-dom": "18.3.1"
   }