Pod placement API issue - dry run doesn't occur for all the stanza

[enp0s3]

/kind bug

What happened:
HCO webhook code doesn't do dry run for the infra section of the pod placement API. Therefore an incorrect configuration may be provided to the HCO CR.

What you expected to happen:
Dry run to fail incorrect configuration of pod placement for infra and workload sections

How to reproduce it (as minimally and precisely as possible):
Provide incorrect configuration to the infra stanza, for example:

spec:
    infra:
      nodePlacement:
        affinity:
          nodeAffinity:
            requiredDuringSchedulingIgnoredDuringExecution:
              nodeSelectorTerms:
              - matchExpressions:
                - key: role.kubernetes.io/master
                  operator: Equal
                  values:
                  - ""
        tolerations:
        - effect: NoSchedule
          key: master
          operator: Exists
    workloads: {}

Environment:

• HCO version (use oc get csv -n kubevirt-hyperconverged):

 » oc get csv -n openshift-cnv
NAME                                      DISPLAY                    VERSION   REPLACES                                  PHASE
kubevirt-hyperconverged-operator.v2.5.0   OpenShift Virtualization   2.5.0     kubevirt-hyperconverged-operator.v2.4.2   Installing

• Kubernetes version (use kubectl version):

Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.2-0-g52c56ce", GitCommit:"b66f2d3a6893be729f1b8660309a59c6e0b69196", GitTreeState:"clean", BuildDate:"2020-07-24T07:19:23Z", GoVersion:"go1.13.4", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.0+d59ce34", GitCommit:"d59ce3486ae3ca3a0c36e5498e56f51594076596", GitTreeState:"clean", BuildDate:"2020-10-08T15:58:07Z", GoVersion:"go1.15.0", Compiler:"gc", Platform:"linux/amd64"}