open-with-dialog: remove automatic setting of support-for-type
open-with-dialog: remove automatic setting of support-for-type

We don't want to hardcode any kind of policy in these widgets/dialogs from
now on.

msteinert/gtk,Distrotech/gtk2,alexlarsson/gtk,chergert/gtk,jadahl/gtk,chergert/gtk,bratsche/gtk-,Distrotech/gtk2,simokivimaki/gtk,ebassi/gtk,alexlarsson/gtk,alexlarsson/gtk,msteinert/gtk,jigpu/gtk,jessevdk/gtk,davidgumberg/gtk,davidgumberg/gtk,Sidnioulz/SandboxGtk,msteinert/gtk,Distrotech/gtk2,grubersjoe/adwaita,bratsche/gtk-,simokivimaki/gtk,jessevdk/gtk,Adamovskiy/gtk,jigpu/gtk,Distrotech/gtk2,msteinert/gtk,Sidnioulz/SandboxGtk,jessevdk/gtk,ahodesuka/gtk,grubersjoe/adwaita,alexlarsson/gtk,Lyude/gtk-,jigpu/gtk,Adamovskiy/gtk,jadahl/gtk,davidt/gtk,alexlarsson/gtk,Lyude/gtk-,bratsche/gtk-,jigpu/gtk,grubersjoe/adwaita,grubersjoe/adwaita,Lyude/gtk-,jigpu/gtk,davidt/gtk,davidt/gtk,Adamovskiy/gtk,Distrotech/gtk2,jessevdk/gtk,ebassi/gtk,chergert/gtk,chergert/gtk,jigpu/gtk,grubersjoe/adwaita,simokivimaki/gtk,davidgumberg/gtk,Adamovskiy/gtk,ahodesuka/gtk,jadahl/gtk,Sidnioulz/SandboxGtk,davidgumberg/gtk,ebassi/gtk,Adamovskiy/gtk,Adamovskiy/gtk,Lyude/gtk-,grubersjoe/adwaita,davidgumberg/gtk,Sidnioulz/SandboxGtk,chergert/gtk,davidt/gtk,jigpu/gtk,alexlarsson/gtk,Distrotech/gtk2,ahodesuka/gtk,chergert/gtk,grubersjoe/adwaita,simokivimaki/gtk,Lyude/gtk-,davidgumberg/gtk,ahodesuka/gtk,davidgumberg/gtk,jadahl/gtk,jessevdk/gtk,chergert/gtk,bratsche/gtk-,ahodesuka/gtk,ebassi/gtk,davidt/gtk,Lyude/gtk-,davidt/gtk,Lyude/gtk-,ebassi/gtk,davidgumberg/gtk,ahodesuka/gtk,Adamovskiy/gtk,alexlarsson/gtk,Lyude/gtk-,grubersjoe/adwaita,jessevdk/gtk,msteinert/gtk,bratsche/gtk-,jadahl/gtk,bratsche/gtk-,Sidnioulz/SandboxGtk,simokivimaki/gtk,chergert/gtk,simokivimaki/gtk,ahodesuka/gtk,jadahl/gtk,alexlarsson/gtk,Adamovskiy/gtk,jadahl/gtk,ahodesuka/gtk,jigpu/gtk,jessevdk/gtk,ebassi/gtk,Sidnioulz/SandboxGtk,jadahl/gtk,msteinert/gtk