systemvm: emit IPv6 prefix block for redundant VPC VRs in radvd.conf (#13127)

Author: jeanvetorello

systemvm/debian/opt/cloud/bin/cs/CsVpcGuestNetwork.py

@@ -107,7 +107,7 @@ def add_radvd_conf(self, entry):
             self.conf.append("    AdvSendAdvert on;")
             self.conf.append("    MinRtrAdvInterval 5;")
             self.conf.append("    MaxRtrAdvInterval 15;")
-            if entry['router_guest_ip6'] == entry['router_guest_ip6_gateway']:
+            if entry['router_guest_ip6'] == entry['router_guest_ip6_gateway'] or self.cl.is_redundant():
                 self.conf.append("    prefix %s" % full_addr)
                 self.conf.append("    {")
                 self.conf.append("        AdvOnLink on;")