make test svelte-4-compatible

Author: dummdidumm

packages/svelte-check/test-error/Index.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
     let count: number = 'oops';
-    let x = $state(0);
+    let x = 0;
     // prettier-ignore
     x ===
         '2';