Enable `Client.get_versions` to get versions from all other clients and compare against those

As mentioned in https://github.com/dask/distributed/issues/6536#issuecomment-1208144451, it would be useful for `Client.get_versions` to get the versions of all other clients and be able to compare against those to detect another client with wrong versions. We may want to hide this feature behind some flag since I suspect that the default use case would be to check the current client against the cluster and ignore potentially mismatching versions on other clients.