OCP 4 IPI installation fails in Azure when v-net subets are pre-configured.

Issue

• Is not possible to install a new version of OCP 4 in Azure with IPI method.
• Older OCP IPI versions works with the same config but not anymore.

• When try to install a cluster it output a similar error:

  ERROR failed to fetch Cluster: failed to generate asset "Cluster": failed to create cluster: failed to create infrastructure manifest: admission webhook "validation.azurecluster.infrastructure.cluster.x-k8s.io" denied the request: AzureCluster.infrastructure.cluster.x-k8s.io "test-repro-0419050-jzg58" is invalid: spec.networkSpec.apiServerLB.frontendIPConfigs[0].privateIP: Invalid value: "172.16.0.52": Internal LB IP address needs to be in control plane subnet range ([172.16.0.0/27])