fqdn: Fix missing IsNil checks in unit tests
fqdn: Fix missing IsNil checks in unit tests

Fixes: 1121202 ("fqdn: L3-aware L7 DNS policy enforcement")
Signed-off-by: Paul Chaignon <a027184a55211cd23e3f3094f1fdc728df5e0500@cilium.io>

cilium/cilium,tklauser/cilium,cilium-team/cilium,michi-covalent/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,cilium-team/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium