fqdn: Fix duplicate CIDRSet generation
fqdn: Fix duplicate CIDRSet generation

When using match patterns, the FQDN cache returns a map of results, each
containing a list of IPs. This can lead to duplicate IPs inserted into the list
of rules.

Fixes: #6541

Signed-off-by: Thomas Graf <5f50a84c1fa3bcff146405017f36aec1a10a9e38@cilium.io>

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