[flexiglass] Parameterize NotificationIconContainerAlwaysOnDisplayViewModelTest

This test was broken while running it on a device, that has Flexiglass
enabled, but the issue was just initializing the class under test too early.

Bug: 376236758
Test: atest NotificationIconContainerAlwaysOnDisplayViewModelTest
Flag: com.android.systemui.scene_container
Change-Id: Ie3bc2695df33b6aceb46956627418d0c3bd01758