ci(app): install playwright browsers before app vitest run

packages/app's vitest config has a browser project backed by playwright
+ chromium; the app-tests job needs the browsers installed the same way
the playwright job already does.

.github/workflows/ci.yml

@@ -132,6 +132,9 @@ jobs:
       - name: Install dependencies
         run: npm install
 
+      - name: Install Playwright browsers
+        run: npx playwright install --with-deps chromium
+
       - name: Build highlight dependency
         run: npm run build --workspace=@getpaseo/highlight