Disable parallelism for node tests

Author: simolus3

packages/node/vitest.config.ts

@@ -3,6 +3,8 @@ import { defineConfig } from 'vitest/config';
 // We need to define an empty config to be part of the vitest works
 export default defineConfig({
   test: {
-    silent: false
+    silent: false,
+    // This doesn't make the tests considerably slower. It may improve reliability for GH actions.
+    fileParallelism: false
   }
 });