[Dual Shade] Fix NotificationStackAppearanceIntegrationTest in DualShade

This ensures these integration tests do not fail when Dual Shade is the
default shade experience in scene container.

Bug: 376411622
Test: Updated integration tests.
Flag: com.android.systemui.scene_container
Change-Id: I961de273dc75d9d2d74eece23f7fd0215595319d