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

Author: renovate[bot]

package.json

@@ -59,7 +59,7 @@
     "@nuxt/eslint-config": "^1.12.1",
     "@nuxt/module-builder": "^1.0.2",
     "@nuxt/schema": "^4.2.2",
-    "@nuxt/test-utils": "^3.23.0",
+    "@nuxt/test-utils": "^4.0.0",
     "@types/node": "^25.0.9",
     "@types/picomatch": "^4.0.2",
     "@unocss/nuxt": "^66.6.0",

playground/package.json

@@ -14,7 +14,7 @@
     "nuxt": "^4.2.2"
   },
   "devDependencies": {
-    "@nuxt/test-utils": "^3.23.0",
+    "@nuxt/test-utils": "^4.0.0",
     "@vue/test-utils": "^2.4.6",
     "playwright-core": "^1.57.0",
     "vitest": "^4.0.17",