Unfolded shade expansion: make it slower to match motion specs

Increasing the split shade full transition distance from 200dp to 400dp.
Make scrim transition 600dp, which 15% larger than the full transition
distance, as it was before as well.

Test: Manually - Recorded before and after videos and compared side by
                 side.
Bug: 267543111
Change-Id: I2ba735011a740ce02e2a3a160325d1b3c9cd1e4a