Update dependency vitest to v4 [SECURITY]

Author: renovate[bot]

packages/svelte-ux/package.json

@@ -48,7 +48,7 @@
     "typescript": "^5.7.3",
     "unist-util-visit": "^5.0.0",
     "vite": "^6.2.0",
-    "vitest": "^3.0.7"
+    "vitest": "^4.0.0"
   },
   "type": "module",
   "dependencies": {