[ovn] stateless NAT is set for FIPs by default instead of stateful, affecting HW Offload

[Itai Levy]

Charmed OpenStack (Yoga / Jammy)

It seems like by default when creating a Floating IP, it will be set in OVN with stateless NAT option:

root@juju-16f12b-1-lxd-9:/home/ubuntu# ovn-nbctl find NAT type=dnat_and_snat
_uuid : aa79f2ab-255d-4ca5-8854-699c0ce25e45
allowed_ext_ips : []
exempted_ext_ips : []
external_ids : {"neutron:fip_external_mac"="fa:16:3e:89:60:a0", "neutron:fip_id"="136d7c6f-4872-4712-8102-63eafcaac190", "neutron:fip_network_id"="5434854a-3c22-4c50-880b-1aa12e2bc7d2", "neutron:fip_port_id"="37a5592b-f2b4-469b-b094-8f3f1de9b5f2", "neutron:revision_number"="14", "neutron:router_name"=neutron-f0821093-56b2-4a3b-86fe-aa982ef90c3f}
external_ip : "10.7.208.90"
external_mac : []
external_port_range : ""
logical_ip : "33.33.33.52"
logical_port : "37a5592b-f2b4-469b-b094-8f3f1de9b5f2"
options : {stateless="true"}
type : dnat_and_snat

This behaviour is affecting HW Offload, and should be reverted to STATEFUL per https://review.opendev.org/c/openstack/neutron/+/838776