Update dependency next to v14.2.21 [SECURITY]

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

Author: renovate[bot]

frontend/package.json

@@ -29,7 +29,7 @@
     "@reduxjs/toolkit": "1.9.7",
     "clsx": "2.1.1",
     "ky": "1.7.4",
-    "next": "14.0.4",
+    "next": "14.2.21",
     "next-redux-wrapper": "8.1.0",
     "react": "18.3.1",
     "react-dom": "18.3.1",