IP not freed when primary asn node label is missing

[Gerrit91]

Leads to unused ip addresses:

cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:03.057786       1 event.go:209] Event(v1.ObjectReference{Kind:"Service", Namespace:"kube-system", Name:"vpn-shoot", UID:"f2bcc242-cc87-4bf1-a5a1-9ca51676fab4", APIVersion:"v1", ResourceVersion:"259", FieldPath:""}): type: 'Normal' reason: 'EnsuringLoadBalancer' Ensuring load balancer
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:03.654823       1 log.go:172] metal-ccm housekeeping | metallb syncher failed: error updating metallb config: node "shoot--local--fra-equ01-default-worker-z1-75b96486f8-8fvpz" misses label: machine.metal-pod.io/network.primary.asn
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:03.741365       1 log.go:172] metal-ccm loadbalancer | acquired ip in network "internet-fra-equ01": 212.34.83.2
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager E1030 10:58:04.051544       1 service_controller.go:219] error processing service kube-system/vpn-shoot (will retry): failed to ensure load balancer for service kube-system/vpn-shoot: node "shoot--local--fra-equ01-default-worker-z1-75b96486f8-8fvpz" misses label: machine.metal-pod.io/network.primary.asn
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:04.052051       1 event.go:209] Event(v1.ObjectReference{Kind:"Service", Namespace:"kube-system", Name:"vpn-shoot", UID:"f2bcc242-cc87-4bf1-a5a1-9ca51676fab4", APIVersion:"v1", ResourceVersion:"259", FieldPath:""}): type: 'Warning' reason: 'CreatingLoadBalancerFailed' Error creating load balancer (will retry): failed to ensure load balancer for service kube-system/vpn-shoot: node "shoot--local--fra-equ01-default-worker-z1-75b96486f8-8fvpz" misses label: machine.metal-pod.io/network.primary.asn
...
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:09.051825       1 service_controller.go:300] Ensuring LB for service kube-system/vpn-shoot
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:09.052160       1 log.go:172] metal-ccm loadbalancer | EnsureLoadBalancer: clusterName "", namespace "kube-system", serviceName "vpn-shoot", nodes "shoot--local--fra-equ01-default-worker-z1-75b96486f8-8fvpz"
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:09.052720       1 event.go:209] Event(v1.ObjectReference{Kind:"Service", Namespace:"kube-system", Name:"vpn-shoot", UID:"f2bcc242-cc87-4bf1-a5a1-9ca51676fab4", APIVersion:"v1", ResourceVersion:"259", FieldPath:""}): type: 'Normal' reason: 'EnsuringLoadBalancer' Ensuring load balancer
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:09.172871       1 log.go:172] metal-ccm loadbalancer | acquired ip in network "internet-fra-equ01": 212.34.83.3
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:09.296879       1 log.go:172] metal-ccm loadbalancer | metallb config updated successfully
cloud-controller-manager-78d46b8cd-lfwhp cloud-controller-manager I1030 10:58:09.297408       1 event.go:209] Event(v1.ObjectReference{Kind:"Service", Namespace:"kube-system", Name:"vpn-shoot", UID:"f2bcc242-cc87-4bf1-a5a1-9ca51676fab4", APIVersion:"v1", ResourceVersion:"259", FieldPath:""}): type: 'Normal' reason: 'EnsuredLoadBalancer' Ensured load balancer