Don't require 'domain' to be present before checking fqdn_ip* grains

[rallytime]

What does this PR do?

Fixes a regression found in #34129 where fqdn_ip4 or fqdn_ip6 grains were empty if the domain grain wasn't set. This removes the check to require the domain name before running the appropriate socket.getaddrinfo calls on the fqdn grain value.

What issues does this PR fix or reference?

Fixes #34129

Previous Behavior

# salt-call grains.item fqdn_ip4
local:
    ----------
    fqdn_ip4:

New Behavior

# salt-call grains.item fqdn_ip4 
local:
    ----------
    fqdn_ip4:
        - 172.16.236.1

Tests written?

No

Please review Salt's Contributing Guide for best practices.

[cachedout]

FYI: Partial revert of #29346