file chooser: Fix up some focus issues
file chooser: Fix up some focus issues

Better to switch the visible stack child early, since GtkStack
has its own focus handling now.

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