listbox: make sure to set selection color for EggListBox
listbox: make sure to set selection color for EggListBox

This fixes a wrong color for selected+hover rows in Contacts.

Distrotech/gnome-themes-standard,DoctorJellyface/gnome-themes-standard,DoctorJellyface/gnome-themes-standard,rgcjonas/adwaita-semidark,rgcjonas/adwaita-semidark,ChrisCummins/gnome-themes-standard,ChrisCummins/gnome-themes-standard,Distrotech/gnome-themes-standard,ChrisCummins/gnome-themes-standard,rgcjonas/adwaita-semidark,rgcjonas/adwaita-semidark,ChrisCummins/gnome-themes-standard,ChrisCummins/gnome-themes-standard