Extensions logs/prefrech are not working in interdomain tests

## Motivation

Currently, prefetch/logs is working only for kubeconfig from evn KUBECONFIG. We should also add support for interdomain cases.

## Solution

Add extension wrapper `foreachcluster` that will simply iterate over all `KUBECONFIG...KUBECONFIG_N` envs and call for each KUBECOFNIG logs/prefetch extension.