Allow repo replication without alternates as a seed

By default, we seed a replicated repository with a snapshot that includes alternates/pool data. However, if ReplicateObjectDeduplicationNetworkMembership is set to true, we should be able to skip the alternates from the snapshot as we would replicate/sync the pool to the target storage and connect the replicated repo to it.

This would be beneficial as it would speed up the replication process and save up disk space that would otherwise have to be cleaned up (see https://gitlab.com/gitlab-org/gitlab/-/issues/440443 for more information).