Config option protocols ospfv3 area <number> range <prefix> not-advertise is broken and behaves exactly same as advertise.

Steps to reproduce:

set protocols ospfv3 area 16 range 2000::/4 not-advertise

• Actual result:**

$ vtysh -c 'show run'
!
router ospf6
area 16 range 2000::/4

Expected result:

$ vtysh -c 'show run'
!
router ospf6
area 16 range 2000::/4 not-advertise

It seems to me that templates/protocols/ospfv3/area/node.tag/range/node.def overwrites area $AREA range $RANGE even if child node no-advertise is set. It seems to me the scripts in that file is used to make child option advertise optional. This PR changes it to only run when children options (advertise, not-advertise) are not set.