Restore notification stack updates during lockscreen-to-shade

Set onLockscreen false during transition to shade
so that #computeHeight
- uses the intrinsic height (increases with swipe open)
- instead of min height (which kept stack height the same)

Fixes: 228511165
Test: NotificationStackSizeCalculatorTest
Test: swipe down on lockscreen notification
	=> notification expands during lockscreen-to-shade transition
Change-Id: I9cb065727cbb82c1dd70999f91f88d6eec132c91