test cases: amp-video hint missing

### Description

Hint not appearing in test case

### Reproduction Steps

1. Go to https://playground.amp.dev/?url=https%3A%2F%2Fpreview.amp.dev%2Fdocumentation%2Fexamples%2Fcomponents%2Famp-video&format=websites
2. Navigate cursor to the 3rd video
3. Hint with the video name should appear but doesn't

---

cc @ampproject/wg-components

Open the linked AMP playground URL and navigate to the third video in the amp-video example. Compare its behavior with the other videos and inspect the test case or component entry point responsible for the hint. Done means the third video displays a hint containing its video name when focused.

Written by the indexing model from the issue text.