Fixed a bug where notifications could be invisible while pulsing

We're now splitting the ambient logic from pulsing, and therefore
have multiple signals that can determine the notification visibility
independently. Previously the two were overlapping leading to invisible
pulsing notifications while the user was dragging down and up.

Test: atest SystemUiTests
Bug: 125942236
Change-Id: I3d6a6f77a1b2943d1c98cefa30a6eadb8519d5ef