Fix m0-2vlan topo prefix_v6 value that causes route_check fail (#12851)

Explicit zeros in prefix_v6 value causes issue in route_check. Need to use simplified form instead

Author: andywongarista

ansible/vars/topo_m0-2vlan.yml

@@ -79,7 +79,7 @@ topology:
           id: 1000
           intfs: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]
           prefix: 192.168.0.1/25
-          prefix_v6: fc02:1000:0:0::1/64
+          prefix_v6: fc02:1000::1/64
           tag: 1000
         Vlan2000:
           id: 2000