Do not recommend sleep at all around browser

[mstoykov]

On https://grafana.com/docs/k6/latest/using-k6-browser/recommended-practices/simulate-user-input-delay/ we do warn users about using sleep, but IMO it should just be a warning to NOT use it at all.

There is no reason to do it, and it will lead to problems as it blocks all execution

[mstoykov]

Also https://grafana.com/docs/k6/latest/using-k6-browser/recommended-practices/sleep-vs-page-wait-for-timeout/ - I do not think this things need sleep and will likely mean that some events will not be handled correctly.