Replace GlobalConfig with Main for ShadeDisplayAwareDetector

From now on we're accepting all classes annotated with @Main, as there are legit reasons to have the "default display" class also for shade classes.

Bug: 362719719
Bug: 374267505
Test: presubmits
Flag: com.android.systemui.shade_window_goes_around
Change-Id: Iea3894f57c81c8b1f3dbc5bdf083ea64c2419075