Support 3-finger swipe on the trackpad to unlock

- Don't handle ACTION_POINTER_DOWN and ACTION_POINTER_UP for trackpad gestures (We cancel multi finger gestures on the screen. We don't want to do that for trackpad gestures since on the trackpad, one finger gesture is reserved for cursor)

Fixes: 270605500
Test: 3-finger swipe up on the lockscreen, and see that it's unlocked
Change-Id: Ida8d9e3d5c543ec7e5619a0df8ce58d8ea02c831