Allow FgsManager to open dialogs on external displays

This uses the context from  ShadeDialogContextRepository when opening a FgsManager dialog (from QS footer).

Bug: 362719719
Bug: 383294128
Test: FgsManagerControllerTest
Flag: com.android.systemui.shade_window_goes_around
Change-Id: I5562d8ddbc171a590f09cf360b91942b1d1fdbba