fix(deps): update dependency next to v15.4.1

Author: renovate[bot]

website/package.json

@@ -13,7 +13,7 @@
   },
   "dependencies": {
     "@theguild/components": "9.7.1",
-    "next": "15.3.3",
+    "next": "15.4.1",
     "react": "^19.0.0",
     "react-dom": "^19.0.0"
   },