dialog: keep action area stretched out
dialog: keep action area stretched out

Adding an extra box in between had the side effect of
making the action area no longer go all across the dialog.
Setting hexpand compensates for this.

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