Remove unused aggregation clusterRoles on refresh

[DnPlas]

Charms that were rewritten from podspec to sidecar pattern do not require kubeflow-roles-operator to create their aggregation clusterRoles because they are now capable of doing that for themselves using lightkube. In that case, the kubeflow-roles-operator must ensure that on upgrade event, it is removing the aggregation clusterRoles that will be duplicated.

Rationale

Two charms will attempt to create, apply, or patch the same resource, which can cause conflicts.

[NohaIhab]

hi @DnPlas
In our upgrade guides we are instructing to remove and re-deploy kubeflow-roles charm for this reason you mentioned.
check it out here and here.
We can definitely improve our upgrade story in the future by handling this in the charm with an upgrade event handler. I'll mark this issue as an enhancement and we can pick it up in Kubeflow 1.9.