fix(deps): update dependency @clerk/nextjs to v6.21.0 (#8070)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

orm/clerk-nextjs/package.json

@@ -9,7 +9,7 @@
     "lint": "next lint"
   },
   "dependencies": {
-    "@clerk/nextjs": "6.20.2",
+    "@clerk/nextjs": "6.21.0",
     "@prisma/client": "6.9.0",
     "next": "15.3.3",
     "react": "19.1.0",