Ignore touch slop threshold for trackpad gestures using gesture nav

Gesture library has a threshold for 3-finger swipes, and if it's recoginized as one, it only reports movement in one axis. There is no point waiting for it to pass the initial threshold, unlike gestures on the screen.

Bug: 291771975
Test: swipe up slowly, observe the smoothness of the gesture nav animation.
Change-Id: I0904efb1d5cd26f6566da46279d0153e19a9618c