GtkDialog: fix invisible action area
GtkDialog: fix invisible action area

When there area explicitly added buttons in the action area,
we were trying to ensure that the action area is visible,
but failed, since we are now hiding the action_box. Fix it
by showing the action_box when things are left in the action
area.

grubersjoe/adwaita,davidgumberg/gtk,grubersjoe/adwaita,chergert/gtk,Adamovskiy/gtk,Lyude/gtk-,davidgumberg/gtk,ahodesuka/gtk,chergert/gtk,davidgumberg/gtk,Lyude/gtk-,ahodesuka/gtk,davidgumberg/gtk,ahodesuka/gtk,jessevdk/gtk,grubersjoe/adwaita,jadahl/gtk,davidgumberg/gtk,jigpu/gtk,ahodesuka/gtk,davidgumberg/gtk,jessevdk/gtk,Adamovskiy/gtk,chergert/gtk,davidgumberg/gtk,Adamovskiy/gtk,Lyude/gtk-,Lyude/gtk-,Lyude/gtk-,Lyude/gtk-,jigpu/gtk,alexlarsson/gtk,Adamovskiy/gtk,alexlarsson/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jadahl/gtk,ahodesuka/gtk,ahodesuka/gtk,grubersjoe/adwaita,Adamovskiy/gtk,jadahl/gtk,alexlarsson/gtk,jessevdk/gtk,chergert/gtk,davidgumberg/gtk,jigpu/gtk,jadahl/gtk,jessevdk/gtk,ahodesuka/gtk,jigpu/gtk,jessevdk/gtk,Lyude/gtk-,jigpu/gtk,grubersjoe/adwaita,jigpu/gtk,alexlarsson/gtk,jessevdk/gtk,chergert/gtk,chergert/gtk,alexlarsson/gtk,jadahl/gtk,jadahl/gtk,jadahl/gtk,chergert/gtk,jessevdk/gtk,ahodesuka/gtk,alexlarsson/gtk,alexlarsson/gtk,Adamovskiy/gtk,grubersjoe/adwaita,Lyude/gtk-,jigpu/gtk,jigpu/gtk,Adamovskiy/gtk,jadahl/gtk,Adamovskiy/gtk,chergert/gtk,alexlarsson/gtk