`microcloud status` will end up in context deadline if member disappeared

In case any of the MicroCloud cluster members goes out of services (maintenance or disaster), running the `microcloud status` command will hit a deadline after 30s trying to contact the offline member's MicroCloud (Microcluster).

This is due to a faulty `GET /core/1.0/cluster` endpoint on Microcluster which tries to contact cluster members even if they are offline.

There already is an open PR with suggestions on how to fix this https://github.com/canonical/microcluster/pull/412.
Some more context https://chat.canonical.com/canonical/pl/dncia5m757ytujm54etu64u7pe.

Start with the `microcloud status` command and the Microcluster `GET /core/1.0/cluster` endpoint described in the issue. Review canonical/microcluster#412 and the linked context before making changes. Done means status no longer waits for the 30-second deadline when a cluster member is offline.

Written by the indexing model from the issue text.