test_host_random: No jinja2 templating in conditional statements

With ansible-core 2.14.12 using jinja2 templating in conditional
statements with ansible_facts['fqdn'] is marked as unsafe and results in
a failure.

The issues with using jinja2 templating in conditional statements for
asserts have been solved and a new server_fqdn fact has been added for
ansible_facts['fqdn'].