Prevent quickscrub when swipe up has already started

Prevents quickscrub from starting when launcher sends the recents
started event to systemui.

Bug: 73351745
Test: manual - swipe up a little from left of home button and
immediately swipe right to start quickscrub

Change-Id: If72275ce591e80d85d8d89e6e0baf7e733d5cb1c