fix: get back the missing scrollbar (#3718)

tests/affine-local/e2e/open-affine.spec.ts

@@ -42,3 +42,11 @@ test.skip('Download client tip', async ({ page }) => {
   );
   await expect(currentDownloadClientTipItem).toBeVisible();
 });
+
+test('Check the class name for the scrollbar', async ({ page }) => {
+  //Because the scroll bar in page mode depends on the class name of blocksuite
+  await openHomePage(page);
+  await waitEditorLoad(page);
+  const affineDocViewport = page.locator('.affine-doc-viewport');
+  await expect(affineDocViewport).toBeVisible();
+});