Description of problem:
We built a cluster with 4.7.0-fc.2 bits and the image registry cluster operator is in degraded state due to pruner service account unable to list the statefulsets in the API group apps at cluster scope: Error from server (Forbidden): statefulsets.apps is forbidden: User "system:serviceaccount:openshift-image-registry:pruner" cannot list resource "statefulsets" in API group "apps" at the cluster scope.

Logs: http://dell-r510-01.perf.lab.eng.rdu2.redhat.com/large-scale/4.7-sdn-kube-1.20/bugs/image-registry/

Version-Release number of selected component (if applicable):
4.7.0-fc.2

How reproducible:
Always, we are also seeing this issue during 4.6.9 -> 4.7.0-fc.2 upgrade

Steps to Reproduce:
1. Install a cluster using 4.7.0-fc.2 bits
2. Monitor the cluster operators, image registry will be in degraded state after  the pruner pod is launched.

Actual results:
image registry cluster operator is in degraded state

Expected results:
image registry cluster operator is healthy and not blocking the upgrades