allow revoking both is_staff and is_superuser in SuperuserManagement
allow revoking both is_staff and is_superuser in SuperuserManagement

previously if you selected nothing
the form would fail (shallowly) with a validation error

dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq