chore(deps): bump next in /e2e/examples/nextjs-agent

Bumps [next](https://github.com/vercel/next.js) from 15.0.3 to 15.1.2.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.0.3...v15.1.2)

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

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

e2e/examples/nextjs-agent/package.json

@@ -10,7 +10,7 @@
   "dependencies": {
     "ai": "^4.0.0",
     "llamaindex": "workspace:*",
-    "next": "15.0.3",
+    "next": "15.1.2",
     "react": "18.3.1",
     "react-dom": "18.3.1"
   },