`retrieveUsedClusterRoles` is erroring, causing false-positive `ClusterRole`, `ClusterRoleBinding` and `RoleBinding` reports

[DrewDevereux]

This issue is well-described by #598, except that it doesn't only cause false-positives in ClusterRole reports, but also in ClusterRoleBinding and RoleBinding reports.

The PR is unmerged, and there doesn't seem to be a corresponding bug report. I'm raising this so that I can link to it.

[yonahd]

Hi @DrewDevereux thanks for the report.
I've been fairly swamped recently, any chance you can take a go at the fix for all 3 resources?

The person who opened the other pr did not complete it