Juju CloudSpec API could leak senstive information

In Juju versions prior to 2.9.57 and 3.6.21, an authorization issue exists in the Controller facade. An authenticated user can call the CloudSpec API method to extract the cloud credentials used to bootstrap the controller. This allows a low-privileged user to access sensitive credentials. This issue is resolved in Juju versions 2.9.57 and 3.6.21.