[th/ipv6-check-addr-order-fix] ipv6: fix expected DHCPv6 address range for @ipv6_check_addr_order
The test passed for "veth" profile, but with "default" profile we have a different IPv6 range and no DHCPv6 server.
Adjust the test to work for both.
Fixes: ecb54371 ('ip: add test for checking order of IP addresses')