GMS-2023-142: Plaintext storage of sensitive data in Rancher API and cluster.management.cattle.io objects

This issue affects Rancher versions from 2.5.0 up to and including 2.5.16, from 2.6.0 up to and including 2.6.9 and 2.7.0. It was discovered that the security advisory CVE-2021-36782 (GHSA-g7j7-h4q8-8w2f), previously released by Rancher, missed addressing some sensitive fields, secret tokens, encryption keys, and SSH keys that were still being stored in plaintext directly on Kubernetes objects like Clusters.