Fix DisplayRepository defaultDisplayOff

The defaultDisplayOff flow was assuming the entire displays were updated when any changed. This caused the event to not be propagated anymore with the enableEfficientDisplayRepository flag.

Bug: 345472038
Test: DisplayRepositoryTest
Flag: com.android.systemui.enable_efficient_display_repository
Change-Id: Ie663f71e37b88b3172e7e47a1d79274886f27434