Remove offscreen canvas types

[etimberg]

Possible fix for #9594

An alternative is to add @types/offscreencanvas as a dependency. I wasn't sure we wanted to do that since we do not have any dependencies right now

[LeeLenaleee]

I think it might be better to add the @types/offscreencanvas as a dependency then because in the performance part of the docs the offscreencanvas is explained as an option and it would be weird if we document it but typing wont allow it.

[kurkle]

I played around with adding the dependency, but could not get everything working with ts 4.4.2 unless library checking was diaabled. Maybe this is a good way for now.