Fix SysUIStateInteractor for lazy states of external displays

Iterating the instances in the repository was not always correct: as instances were created lazily, it might have happened that the SysUI State for an external display was not there.

Now we're iterating all displays instead.

+ a performance optimization: changes from the interactor are committed at the end, after all the StateChanges are applied to each SysUI state. This makes sure to minimize the state propagated to launcher.

Bug: 362719719
Bug: 398011576
Test: SysUIStatePerDisplayInteractorTest
Flag: com.android.systemui.shade_window_goes_around
Change-Id: Ib0178a332a1e1f05d70ba3da52334497ba766557