Customize camera gesture vibrator pattern

Value for camera gesture vibrator pattern changes between versions, e.g.
it was changed from 1000 to 750 in 7.0, which seems arbitrary and OEMs do
not stick with this value, but change it according to their requirements.

This change allows the value to be customized using overlays.

Bug: 32789246
Change-Id: I19e59d1fa191657a8575c486008db3991b347fc5