Wan federation doesn't work with FQDN node name

#### Related Topic on Hashicorp Discuss

[Connection failure in federation between VMs (primary) and kubernetes](https://discuss.hashicorp.com/t/connection-failure-in-federation-between-vms-primary-and-kubernetes/37201)

#### Overview of the Issue

I wanted to federate a consul cluster running in k3s (named: `dc2`) to a consul cluster running on VMs (named: `dc1`).
The nodes of the VM cluster have a node name in FQDN format (eg `ceph-1.hirsingue.infra.mydomain.fr`) which causes the following error in the logs (`dc2` consul server) and prevents the federation from continuing:

```
2022-03-22T08:42:47.170Z [INFO] agent: (WAN) joined: number_of_nodes=1
2022-03-22T08:42:47.170Z [INFO] agent: Join cluster completed. Synced with initial agents: cluster=WAN num_agents=1
2022-03-22T08:42:47.170Z [INFO] agent.server: Handled event for server in area: event=member-join server=ceph-2.hirsingue.infra.mydomain.fr.dc1 area=wan
2022-03-22T08:42:47.657Z [ERROR] agent.server.memberlist.wan: memberlist: Failed to send gossip to 192.168.11.11:8302: node name does not encode a datacenter: ceph-2.hirsingue.infra.mydomain.fr.dc1
```

#### Reproduction Steps

This should be similar for any cluster type, but in my case :
- have a cluster in VMs up and running with node name in FQDN format.
eg: `ceph-1.hirsingue.infra.mydomain.fr`
- create and distribute TLS certificates on VM servers
eg: `consul tls cert create -server -dc dc1 -node ceph-1.hirsingue.infra.mydomain.fr`
- following this documentation: [Federation between VMs (primary) and Kubernetes](https://www.consul.io/docs/k8s/installation/multi-cluster/vms-and-kubernetes#kubernetes-as-the-secondary) to federate a mononode k3s.

### Consul info for dc1 and dc2 server

DC2 Server info

```
agent:
check_monitors = 0
check_ttls = 0
checks = 0
services = 0
build:
prerelease =
revision = 37c7d06b
version = 1.11.2
consul:
acl = enabled
bootstrap = true
known_datacenters = 2
leader = true
leader_addr = 10.42.0.89:8300
server = true
raft:
applied_index = 18196
commit_index = 18196
fsm_pending = 0
last_contact = 0
last_log_index = 18196
last_log_term = 29
last_snapshot_index = 16385
last_snapshot_term = 29
latest_configuration = [{Suffrage:Voter ID:c6226cd1-b686-5e17-cf23-22bbc5d42e06 Address:10.42.0.89:8300}]
latest_configuration_index = 0
num_peers = 0
protocol_version = 3
protocol_version_max = 3
protocol_version_min = 0
snapshot_version_max = 1
snapshot_version_min = 0
state = Leader
term = 29
runtime:
arch = amd64
cpu_count = 8
goroutines = 185
max_procs = 8
os = linux
version = go1.17.5
serf_lan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 29
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 85
members = 2
query_queue = 0
query_time = 1
serf_wan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 1
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 2533
members = 4
query_queue = 0
query_time = 1
```

DC1 Server info

```
root@ceph-1:~ # consul info
agent:
check_monitors = 0
check_ttls = 1
checks = 2
services = 2
build:
prerelease =
revision = 37c7d06b
version = 1.11.2
consul:
acl = enabled
bootstrap = false
known_datacenters = 2
leader = false
leader_addr = 192.168.11.12:8300
server = true
raft:
applied_index = 445310
commit_index = 445310
fsm_pending = 0
last_contact = 13.990512ms
last_log_index = 445310
last_log_term = 7102
last_snapshot_index = 442448
last_snapshot_term = 7102
latest_configuration = [{Suffrage:Voter ID:d893d4cf-d43f-13e2-38b4-ee593d86d829 Address:192.168.11.11:8300} {Suffrage:Voter ID:0781d8ae-72a5-2a4b-9892-2aba24ea38f7 Address:192.168.11.12:8300} {Suffrage:Voter ID:23de9416-f021-b420-a9ef-6dd73313c54b Address:192.168.11.10:8300}]
latest_configuration_index = 0
num_peers = 2
protocol_version = 3
protocol_version_max = 3
protocol_version_min = 0
snapshot_version_max = 1
snapshot_version_min = 0
state = Follower
term = 7102
runtime:
arch = amd64
cpu_count = 8
goroutines = 177
max_procs = 8
os = linux
version = go1.17.5
serf_lan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 902
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 14504
members = 3
query_queue = 0
query_time = 1
serf_wan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 1
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 2533
members = 4
query_queue = 0
query_time = 1
```

### Operating system and Environment details

VMs OS:
```
Description: Ubuntu 21.04
Release: 21.04
```

Thanks for your help!

No source file or test is named. Start by tracing the WAN memberlist handling associated with the reported “node name does not encode a datacenter” error, then reproduce federation with an FQDN node name; done means the clusters federate successfully without the logged failure.

Written by the indexing model from the issue text.