Enable ARO MHC on infra nodes (#4832)

Author: tsatam

pkg/operator/controllers/machinehealthcheck/staticresources/machinehealthcheck.yaml

@@ -9,7 +9,6 @@ spec:
     - key: machine.openshift.io/cluster-api-machine-role
       operator: NotIn
       values:
-      - "infra"
       - "master"
     - key: machine.openshift.io/cluster-api-machineset
       operator: Exists