fix(web): shorten setFocusTimer()

Fixes #5909.

The `setFocusTimer()` delay was 1000ms. However, it seems that a much
shorter delay accomplishes the same outcome for switching between
controls, as the important factor is to block asynchronously-arriving
events from cancelling the OSK / focus controls for touch alias
elements.

I have set the delay to 50ms. This is fast enough that a click in a
control followed by a click on the page area will always cancel the OSK,
but gives the space needed for queued focus/blur events have time to be
processed before cancelling the timer.