feat(watchOnce): allow watching until certain condition is met

[BR0kEN-]

Description

Add the optional until callback to the watchOnce options to keep watching until certain condition is met.

[antfu]

I am not sure about this, having this would change the semantic of watchOnce - that might end up the handler being called multiple times. I guess it might be better for you to just call the stop handler returned by watch when you no longer need it.

Thank you