fix: octavia-api broken in multinode OVS

When kolla_enable_ovn is false, fallback to amphora driver

Author: elelaysh

etc/kayobe/environments/ci-multinode/kolla/globals.yml

@@ -49,7 +49,7 @@ opensearch_heap_size: 1g
 
 # Octavia load balancer configuration
 octavia_auto_configure: "no"
-octavia_provider_drivers: "ovn:OVN provider"
+octavia_provider_drivers: "{{ kolla_enable_ovn | ternary('ovn:OVN provider', 'amphora') }}"
 octavia_provider_agents: "ovn"
 
 # Manila CephFS configuration