Remove flag dependency of `status_bar_connected_displays`

`status_bar_connected_displays` was depending on
`status_bar_simple_fragment`. Since both are fairly independent, and
have different timelines, it is best to remove the dependency.

Changes:
- StatusBarOrchestrator related changes are now behind
  `status_bar_connected_displays` instead of
  `status_bar_simple_fragment`.
- Dagger changes:
 - StatusBarInitializer is CoreStartable iff
   `status_bar_simple_fragment` is enabled
 - StatusBarOrchestrator is never CoreStartable. It will always be
   started via MultiDisplayStatusBarStarter.

Test: CentralSurfacesImplTest.java
Test: StatusBarInitializerTest.kt
Test: StatusBarOrchestratorTest.kt
Test: Manually - Build and run with both flags enabled, disabled, and
      enabled independently.
Flag: com.android.systemui.status_bar_connected_displays
Bug: 362720336
Change-Id: I2f464b39353b1db9e5f8d01991b5f0b75a37c654