Vitest 4.0.6 (#642)

* Upgrade vitest. Update config. Fix tests.

* Update workflow for node 20.

Author: jbouder

.github/workflows/test-ui.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Set up Node environment
         uses: actions/setup-node@v3
         with:
-          node-version: 18.x
+          node-version: 20.x
 
       - name: Install dependencies
         run: npm ci