Add missing diagram to FWE implicit animations page

[parlough]

Page URL

https://docs.flutter.dev/tutorial/ui/7-implicit-animations

Page source

https://github.com/flutter/website/blob/main/src/content/tutorial/ui/7-implicit-animations.md

Describe the problem

There's a TODO to add a diagram.

Expected fix

No response

Additional context

No response

I would like to fix this problem.

• [ ] I will try and fix this problem on docs.flutter.dev.

[ericwindmill]

Oops