panic when setting disableExternalNetwork: true

[faelis]

/kind bug

What steps did you take and what happened:
I create a openstackcluster like this :

apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: OpenStackCluster
metadata:
  name: foo
  namespace: foo-cluster
spec:
  identityRef:
    cloudName: idf1
    name: clouds.idf1.opp
  managedSubnets:
  - cidr: 192.168.100.0/24
  disableExternalNetwork: true

And this happen in the 'capo-controller-manager' :

I1119 10:29:16.598608       1 controller.go:110] "Observed a panic in reconciler: runtime error: invalid memory address or nil pointer dereference" controller="openstackcluster" controllerGroup="infrastructure.cluster.x-k8s.io" controllerKind="OpenStackCluster" OpenStackCluster="foo-cluster/foo" namespace="foo-cluster" name="foo" reconcileID="29b6c15b-d500-4fc8-8a1f-d56223a4e226"
panic: runtime error: invalid memory address or nil pointer dereference [recovered]                                                                                                                panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x1b774f9]

goroutine 357 [running]:
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile.func1()                                                                                                             /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:111 +0x1e5
panic({0x1dccbe0?, 0x362a670?})
        /usr/local/go/src/runtime/panic.go:770 +0x132
sigs.k8s.io/cluster-api-provider-openstack/pkg/cloud/services/networking.(*Service).GetOrCreateFloatingIP(0xc000392bd0, {0x242a030, 0xc0004a4588}, 0x1cce7a0?, {0xc000a72680?, 0x1cce7a0?}, 0xc000afcae0?)
        /workspace/pkg/cloud/services/networking/floatingip.go:53 +0xf9
sigs.k8s.io/cluster-api-provider-openstack/controllers.reconcileControlPlaneEndpoint(0xc000392bd0?, 0xc0004a4588?, 0xc0004a4588, {0xc000a72680?, 0x1e?})
        /workspace/controllers/openstackcluster_controller.go:804 +0x290
sigs.k8s.io/cluster-api-provider-openstack/controllers.reconcileNetworkComponents(0xc000b00db0, 0xc0005fc000, 0xc0004a4588)
        /workspace/controllers/openstackcluster_controller.go:685 +0x428
sigs.k8s.io/cluster-api-provider-openstack/controllers.(*OpenStackClusterReconciler).reconcileNormal(0xc0003e5ec0, {0x2440510, 0xc00076e660}, 0xc000b00db0, 0xc0005fc000, 0xc0004a4588)
        /workspace/controllers/openstackcluster_controller.go:312 +0xf2
sigs.k8s.io/cluster-api-provider-openstack/controllers.(*OpenStackClusterReconciler).Reconcile(0xc0003e5ec0, {0x2440510, 0xc00076e660}, {{{0xc0008049f0?, 0x0?}, {0xc0008049ec?, 0xc0002a5d10?}}})
        /workspace/controllers/openstackcluster_controller.go:135 +0x6d0
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile(0x2446788?, {0x2440510?, 0xc00076e660?}, {{{0xc0008049f0?, 0xb?}, {0xc0008049ec?, 0x0?}}})
        /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:114 +0xb7
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler(0xc0001668f0, {0x2440548, 0xc0005f8b90}, {0x1e96420, 0xc000386680})
        /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:311 +0x3bc
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem(0xc0001668f0, {0x2440548, 0xc0005f8b90})
        /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:261 +0x1be
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2()                                                                                                               /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:222 +0x79
created by sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2 in goroutine 184
        /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:218 +0x486

What did you expect to happen:
No panic in the controller.

Anything else you would like to add:
i think it's due to this

cluster-api-provider-openstack/pkg/cloud/services/networking/floatingip.go

Line 53 in 7800252

fpCreateOpts.FloatingNetworkID = openStackCluster.Status.ExternalNetwork.ID

Go try to get the id of the externalnetwork, but externalnetwork is disabled

Environment:

• Cluster API Provider OpenStack version (Or git rev-parse HEAD if manually built): 0.11.2
• Cluster-API version: 1.8.4
• OpenStack version: yoga
• Minikube/KIND version: NA
• Kubernetes version (use kubectl version): 1.31
• OS (e.g. from /etc/os-release): talos