manifest: Enable gtk3 installed tests
manifest: Enable gtk3 installed tests

GNOME/gnome-ostree,vrutkovs/vrutkovs.github.io,vrutkovs/vrutkovs.github.io,chergert/gnome-continuous,GNOME/gnome-ostree,vrutkovs/vrutkovs.github.io,chergert/gnome-continuous,GNOME/gnome-ostree,chergert/gnome-continuous