fix: wait for two animation frames to prevent flaky test

The waitForAnimationFrame helper was only waiting for one animation frame,
but due to the round-trip time of Playwright's page.evaluate, maquette's
scheduled render could fire before our callback was registered.

Waiting for two animation frames ensures maquette's render completes before
the test continues.

Author: johan-gorter

browser-tests/tests/TodoPage.ts

@@ -36,11 +36,14 @@ export class TodoPage {
   }
 
   /**
-   * Wait for one animation frame to allow maquette to render
+   * Wait for two animation frames to allow maquette to render
    */
   async waitForAnimationFrame(): Promise<void> {
     await this.page.evaluate(
-      () => new Promise((resolve) => requestAnimationFrame(() => resolve(undefined)))
+      () =>
+        new Promise((resolve) =>
+          requestAnimationFrame(() => requestAnimationFrame(() => resolve(undefined)))
+        )
     );
   }