Don't reserve vertical space for subtitles in headerbars
This fixes a problem verified with GTK 3.22.24. Possible cause summarized here: https://gitlab.gnome.org/GNOME/gtk/-/issues/2761
This fixes a problem verified with GTK 3.22.24. Possible cause summarized here: https://gitlab.gnome.org/GNOME/gtk/-/issues/2761