Revert "Partial revert of "Prepare LightBarController for multi display""

This reverts commit 63f2de1e and fixes
merge conflicts

Reason for revert: PerDisplayStore now handles display not present, it was fixed in b/384496996

Change-Id: Iad16e48bc727373fe9f518461e3ba60ac2e9e22e
Test: NavigationBarTest.java
Test: LightBarControllerTest.java
Flag: com.android.systemui.shared.status_bar_connected_displays