Implement toBeInViewport assertion

[kwojcik]

Clear and concise description of the problem

I've been implementing lot of scrolling things recently, and using getBoundingClientRect or IntersectionObserver in tests introduces clutter and makes tests less readable.

Suggested solution

Implement toBeInViewport

Alternative

No response

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.