combobox: Remove unused argument
combobox: Remove unused argument

The visible check is always FALSE, so no need to keep the code around.

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