Fit and finish for camera affordance animations in keyguard

- better timing
- animate warp back when finger is released.
- Improve on/off screen animation for warped view
- Re-use existing constants for consistent timing.
- Hide the challenge area when the camera page is settling.
- Reduce jank when camera page starts snap transition.
- Prevent warping from going to previous page
- Smoothly blend between PagedView and Warp animations when scrolling starts.

Bug 10991981

Change-Id: I84822790a040a2ce2dcea60a9486f01df9cff105