Rancher: Ownership-less ClusterRole overwrite via attacker-controlled cr-name annotation on GlobalRole

A flaw was found in Rancher Manager. The GlobalRole controller derived the target ClusterRole name from the user-settable `authz.management.cattle.io/cr-name` annotation and overwrote that object's rules without verifying ownership. A user with delegated GlobalRole create or update permission could point the annotation at any existing ClusterRole, such as `cluster-admin`, and revoke the permissions of every principal bound to it. The change persists after the malicious GlobalRole is deleted.

This issue affects Rancher: before 2.15.1.