Incorrect validation for resources while OCP 4 IPI installation on Vsphere

Issue

• While trying the OCP 4.6 Vsphere IPI installation, we tried creating the instances below the recommended value to see if the IPI installation completes. The installer creates the master vms in vsphere:

NAME                      STATUS   ROLES    AGE    VERSION
ocp46ipi-mnj6b-master-0   Ready    master   144m   v1.19.0-rc.2+514f31a
ocp46ipi-mnj6b-master-1   Ready    master   143m   v1.19.0-rc.2+514f31a
ocp46ipi-mnj6b-master-2   Ready    master   143m   v1.19.0-rc.2+514f31a

• And the installer fails as the ingress and oauth were looking for worker nodes:

# oc get events -n openshift-machine-api
3s          Warning   ReconcileError      machineset/ocp46ipi-mnj6b-worker                    failed to sync machines: admission webhook "validation.machine.machine.openshift.io" denied the request: providerSpec.diskGiB: Invalid value: 50: diskGiB is below minimum value (120); admission webhook "validation.machine.machine.openshift.io" denied the request: providerSpec.diskGiB: Invalid value: 50: diskGiB is below minimum value (120); admission webhook "validation.machine.machine.openshift.io" denied the request: providerSpec.diskGiB: Invalid value: 50: diskGiB is below minimum value (120); admission webhook "validation.machine.machine.openshift.io" denied the request: providerSpec.diskGiB: Invalid value: 50: diskGiB is below minimum value (120)