Lockscreen spacing to UX specs

Reduce spacing between smartspace and notification area. Remove
concept of 'expanded clock position' from
KeyguardClockPositionAlgorithm, as it was only used when content was
vertically centered. Similarly, remove difference between
bypass/non-bypass height as the two layouts now match.

Fixes: 183008450
Fixes: 190831603
Test: atest KeyguardClockPositionAlgorithmTest
Change-Id: Ie274e34eb61a876166c11e4f4fa3b9d95ef49888