Controls UI - Do not throttle drag events

For range controls, many users will want to swipe multiple times in
order to set the desired level. Currently, if the user swipes twice in
fast succession, only the first set point will be sent. Do not block
these swipe events from being sent to the corresponding service.

Fixes: 162850998
Test: manual swipes on range controls
Change-Id: Ib3be25bd362b411b9cd089d49edec7747820d0e7