When logging into a JWT auth method, we need to explicitly supply the Consul
admin partition if the local Consul agent is in a partition. We can't derive
this from agent configuration because the Consul agent's configuration is
canonical, so instead we get the partition from the fingerprint (if
available). This changeset updates the Consul client constructor so that we
close over the partition from the fingerprint.
Ref: https://hashicorp.atlassian.net/browse/NET-9451
140747240f