operator NS manifest: Set empty openshift.io/run-level
We dropped the run-level label from this namespace back in 4.5 but because of how the cluster-version operator reconciles manifest labels, dropping a label from the manifest does not remove it from the in-cluster resource when old clusters are updated into the new manifest. This commit uses the approach the cluster-version operator used to drop its run-level, by setting the value to an empty string, which the run-level-consuming code treats identically to an unset label. This avoids errors about: ...container has runAsNonRoot and image will run as root... when updating to 4.11 in case the operator deployment manifest specifically requests runAsNonRoot: true.