Add validation if proper x-constraint name not specified

[alakendu]

Version information
https://github.com/open-traffic-generator/snappi-ixnetwork/releases/tag/v0.7.8

Describe the bug
x-constraint will use to identify referential integrity targets. User may specify any string without following grammar. It will better to validate if that is string is proper x-constraint

We need validation as ipv4_name set as p1_eth1.name which is invalid

p1_d1 = config.devices.device(name='p1_d1')[-1]
p1_eth1 = p1_d1.ethernets.ethernet(port_name="p1")[-1]
p1_eth1.name = 'p1_eth1'
p1_ip1 = p1_eth1.ipv4_addresses.ipv4(name='p1_ip1',
                                     address='20.20.20.2',
                                     gateway='20.20.20.1')[-1]
p1_bgp = p1_d1.bgp
p1_bgp_iface = (p1_bgp.ipv4_interfaces
                .v4interface(ipv4_name=p1_eth1.name)[-1])

To Reproduce
This will end up with several exception which will not pinpoint exact issue.

Expected behavior
solution should raise exception for incorrect x-constraint

Additional context
It will better if we incorporate similar validation within snappi and gosnappi