Function blackout_target::find_partition

pub async fn find_partition(
    partition_label: &str,
    device_dir: Option<&DirectoryProxy>
) -> Result<ControllerProxy>

During the test or verify steps, finds a block device which represents an fvm partition named [partition_label]. If [device_path] is provided, this assumes the partition is on that device. Returns the topological path to the device, only returning once the device is enumerated, so it can be used immediately.