server: allow adding non-overlapping ipv6 ranges in same vlan (apache#11556)

Fixes apache#11527

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>
Co-authored-by: Wei Zhou <weizhou@apache.org>

Author: shwstppr

server/src/main/java/com/cloud/configuration/ConfigurationManagerImpl.java

@@ -5173,10 +5173,6 @@ public Vlan createVlanAndPublicIpRange(final long zoneId, final long networkId,
                                 vlan.getVlanTag()));
                     }
                 }
-                if (NetUtils.isSameIsolationId(vlanId, vlan.getVlanTag()) && !vlanIp6Gateway.equals(vlan.getIp6Gateway())) {
-                    throw new InvalidParameterValueException(String.format("The IP range with tag: %s has already been added with gateway %s. Please specify a different tag.",
-                            vlan.getVlanTag(), vlan.getIp6Gateway()));
-                }
             }
         }