To increase usability, fonts for gtk applications is now set in respective fonts kcm, instead of separate gtk kcm.
Not sure if we should provide option to modify font only for gtk applications: why would anyone need to set different fonts for gnome and kde apps?
Note: if fonts configuration option will be removed from kde-gtk-config, this patch will be needed (D21524), so gtk2rc file won't be overridden without font string.
Depends on D21524
BUG: 138866