test(useOverlay): add composable tests (#4482)

Co-authored-by: Benjamin Canac <canacb1@gmail.com>

vitest.config.ts

@@ -6,7 +6,7 @@ export default defineVitestConfig({
     testTimeout: 1000,
     globals: true,
     silent: true,
-    include: ['./test/components/**.spec.ts'],
+    include: ['./test/components/**.spec.ts', './test/composables/**.spec.ts'],
     environment: 'nuxt',
     environmentOptions: {
       nuxt: {