Tutorial part 1 - Automated Testing - animation

### ISSUE:

Just a minor one here--a difference between what's described and what's displayed.

Beneath the second "Zoey says..." there's this note:

> "If you watch really carefully, you can see our test robot roaming around our app and clicking links:"

> "It happens really quickly though—blink and you might miss it! In fact, I had to slow this animation down by a hundred times just so you can see it in action.

Instead of a gif or a video, there's a static png file.

### PROPOSAL:

Either add a gif here to demonstrate the test in action, or modify the note to describe the existing screenshot of what a person should expect to see when all tests pass.