build(deps): bump next in /packages/examples/next-15

Bumps [next](https://github.com/vercel/next.js) from 15.5.14 to 15.5.15.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.5.14...v15.5.15)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.5.15
  dependency-type: direct:production
...

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

Author: dependabot[bot]

packages/examples/next-15/package.json

@@ -11,7 +11,7 @@
     "@react-pdf/renderer": "^4.5.1",
     "react": "19.1.0",
     "react-dom": "19.1.0",
-    "next": "15.5.14"
+    "next": "15.5.15"
   },
   "devDependencies": {
     "postcss": "^8",