chore(deps): update devdependency @nuxt/test-utils to v4

Author: renovate[bot]

package.json

@@ -52,7 +52,7 @@
         "@nuxt/eslint-config": "^1.11.0",
         "@nuxt/kit": "^4.2.1",
         "@nuxt/module-builder": "^1.0.2",
-        "@nuxt/test-utils": "^3.21.0",
+        "@nuxt/test-utils": "^4.0.0",
         "changelogen": "^0.6.2",
         "crawler-user-agents": "^1.22.0",
         "eslint": "^9.39.1",