GtkStack: Remove useless function calls
GtkStack: Remove useless function calls

These both just use the default values anyway.

jadahl/gtk,chergert/gtk,davidgumberg/gtk,alexlarsson/gtk,grubersjoe/adwaita,Adamovskiy/gtk,chergert/gtk,grubersjoe/adwaita,grubersjoe/adwaita,davidgumberg/gtk,grubersjoe/adwaita,grubersjoe/adwaita,alexlarsson/gtk,davidgumberg/gtk,jadahl/gtk,grubersjoe/adwaita,chergert/gtk,davidgumberg/gtk,jadahl/gtk,Adamovskiy/gtk,jadahl/gtk,chergert/gtk,davidgumberg/gtk,grubersjoe/adwaita,jigpu/gtk,Adamovskiy/gtk,jigpu/gtk,jigpu/gtk,alexlarsson/gtk,alexlarsson/gtk,davidgumberg/gtk,alexlarsson/gtk,jigpu/gtk,Adamovskiy/gtk,jadahl/gtk,jadahl/gtk,chergert/gtk,Adamovskiy/gtk,jadahl/gtk,jigpu/gtk,chergert/gtk,Adamovskiy/gtk,alexlarsson/gtk,chergert/gtk,davidgumberg/gtk,grubersjoe/adwaita,Adamovskiy/gtk,davidgumberg/gtk,jigpu/gtk,jadahl/gtk,alexlarsson/gtk,chergert/gtk,jigpu/gtk,jigpu/gtk,alexlarsson/gtk,Adamovskiy/gtk