Bump next from 14.2.15 to 14.2.21

Bumps [next](https://github.com/vercel/next.js) from 14.2.15 to 14.2.21.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/compare/v14.2.15...v14.2.21)

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

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

package.json

@@ -14,7 +14,7 @@
   "dependencies": {
     "clsx": "^2.1.0",
     "concurrently": "^8.2.2",
-    "next": "^14.2.15",
+    "next": "^14.2.21",
     "react": "^18",
     "react-confetti": "^6.1.0",
     "react-dom": "^18",