build(deps): bump next from 16.2.4 to 16.2.6 in /tests/test-nextjs

Bumps [next](https://github.com/vercel/next.js) from 16.2.4 to 16.2.6.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v16.2.4...v16.2.6)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 16.2.6
  dependency-type: direct:production
...

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

Author: dependabot[bot]

tests/test-nextjs/package-lock.json

@@ -26,7 +26,7 @@
     "isbinaryfile": "^6.0.0",
     "jsdom": "28.0.0",
     "memory-cache": "^0.2.0",
-    "next": "^16.2.2",
+    "next": "^16.2.6",
     "picocolors": "^1.1.1",
     "react": "^19.2.4",
     "react-dom": "^19.2.4",