Automatic merge from submit-queue (batch tested with PRs 44412, 44810, 47130, 46017, 47829)

Return clusterErr rather than err

The updateClusterIngressUIDToMasters() should return clusterErr, not err.
If the 'err' of 'masterCluster, masterUID, err := ic.getMasterCluster()' is nil and the 'clusterErr' of 'clusterObj, clusterErr := api.Scheme.DeepCopy(cluster)' is not nil, updateClusterIngressUIDToMasters() will return ("", nil).

And do not log fallbackUID when fallbackUID is nil.