consul auto-encryption fails on IPv6-only cluster

#### Overview of the Issue

Client certificate distribution fails on a IPv6-only cluster using the auto-encryption method.

### Consul info

Server info

```
agent:
check_monitors = 0
check_ttls = 0
checks = 3
services = 3
build:
prerelease =
revision = 7bbad6fe
version = 1.10.4
consul:
acl = enabled
bootstrap = false
known_datacenters = 1
leader = false
leader_addr = [2a05:d014:d9e:c305:b0bc:d053:f019:ed77]:8300
server = true
raft:
applied_index = 9789
commit_index = 9789
fsm_pending = 0
last_contact = 83.945604ms
last_log_index = 9789
last_log_term = 4
last_snapshot_index = 0
last_snapshot_term = 0
latest_configuration = [{Suffrage:Voter ID:22da461e-212d-76e2-95e5-0fb99ae5097e Address:[2a05:d014:d9e:c303:e4d3:d281:a61d:8ebd]:8300} {Suffrage:Voter ID:6d370695-dac6-5205-6070-325b3cff86a8 Address:[2a05:d014:d9e:c305:b0bc:d053:f019:ed77]:8300} {Suffrage:Voter ID:c4ed1b5a-859f-ca1a-f6dd-ab2555f8e7cf Address:[2a05:d014:d9e:c304:fc9f:38cd:a734:5022]: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 = 4
runtime:
arch = arm64
cpu_count = 2
goroutines = 110
max_procs = 2
os = linux
version = go1.16.10
serf_lan:
coordinate_resets = 0
encrypted = true
event_queue = 0
event_time = 4
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 7
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 = 1
members = 1
query_queue = 0
query_time = 1
```

### Operating system and Environment details

ARM64 Centos Stream 8 Nodes on AWS EC2

### Log Fragments

```
systemd[1]: Started "HashiCorp Consul - A service mesh solution".
consul[12945]: ==> Starting Consul agent...
consul[12945]: Version: '1.10.4'
consul[12945]: Node ID: '38f1b91f-65a2-58a3-2e61-8ba9e11e5fb4'
consul[12945]: Node name: 'i-0e39a8a2b3460b871'
consul[12945]: Datacenter: 'eu-central-1' (Segment: '')
consul[12945]: Server: false (Bootstrap: false)
consul[12945]: Client Addr: [127.0.0.1 ::1] (HTTP: 8500, HTTPS: -1, gRPC: -1, DNS: 8600)
consul[12945]: Cluster Addr: 2a05:d014:d9e:c303:e4d0:6e78:b6d0:a903 (LAN: 8301, WAN: 8302)
consul[12945]: Encrypt: Gossip: true, TLS-Outgoing: true, TLS-Incoming: true, Auto-Encrypt-TLS: true
consul[12945]: ==> Log data will now stream in as it occurs:
consul[12945]: 2021-12-15T03:41:57.224Z [WARN] agent: "autopilot.redundancy_zone_tag" is a Consul Enterprise configuration and will have no effect
consul[12945]: 2021-12-15T03:41:57.225Z [WARN] agent: "autopilot.disable_upgrade_migration" is a Consul Enterprise configuration and will have no effect
consul[12945]: 2021-12-15T03:41:57.249Z [WARN] agent.auto_config: "autopilot.redundancy_zone_tag" is a Consul Enterprise configuration and will have no effect
consul[12945]: 2021-12-15T03:41:57.249Z [WARN] agent.auto_config: "autopilot.disable_upgrade_migration" is a Consul Enterprise configuration and will have no effect
consul[12945]: 2021-12-15T03:41:57.270Z [INFO] agent.auto_config: discover-aws: Region is eu-central-1
consul[12945]: 2021-12-15T03:41:57.270Z [INFO] agent.auto_config: discover-aws: Filter instances with packer-aws-stack=packer-aws-stack-server
consul[12945]: 2021-12-15T03:41:57.463Z [INFO] agent.auto_config: discover-aws: Instance i-09cc796081995cdc1 has IPv6 2a05:d014:d9e:c303:e4d3:d281:a61d:8ebd on NetworkInterfaceId eni-0eb12a1d1acec6e61
consul[12945]: 2021-12-15T03:41:57.463Z [INFO] agent.auto_config: discover-aws: Instance i-0cc65f132aaa635ba has IPv6 2a05:d014:d9e:c304:fc9f:38cd:a734:5022 on NetworkInterfaceId eni-0f8a76deed0c941fa
consul[12945]: 2021-12-15T03:41:57.463Z [INFO] agent.auto_config: discover-aws: Instance i-09f5a19c8ee3f55cb has IPv6 2a05:d014:d9e:c305:b0bc:d053:f019:ed77 on NetworkInterfaceId eni-06c9484734c3d2e4d
consul[12945]: 2021-12-15T03:41:57.463Z [WARN] agent.auto_config: error splitting host address into IP and port: address=2a05:d014:d9e:c303:e4d3:d281:a61d:8ebd error="address 2a05:d014:d9e:c303:e4d3:d281:a61d:8ebd: too many colons in address"
consul[12945]: 2021-12-15T03:41:57.463Z [WARN] agent.auto_config: error splitting host address into IP and port: address=2a05:d014:d9e:c304:fc9f:38cd:a734:5022 error="address 2a05:d014:d9e:c304:fc9f:38cd:a734:5022: too many colons in address"
consul[12945]: 2021-12-15T03:41:57.463Z [WARN] agent.auto_config: error splitting host address into IP and port: address=2a05:d014:d9e:c305:b0bc:d053:f019:ed77 error="address 2a05:d014:d9e:c305:b0bc:d053:f019:ed77: too many colons in address"
consul[12945]: 2021-12-15T03:41:57.463Z [ERROR] agent.auto_config: no auto-encrypt server addresses available for use
consul[12945]: 2021-12-15T03:41:57.463Z [INFO] agent.auto_config: discover-aws: Region is eu-central-1
consul[12945]: 2021-12-15T03:41:57.464Z [INFO] agent.auto_config: discover-aws: Filter instances with packer-aws-stack=packer-aws-stack-server
consul[12945]: 2021-12-15T03:41:57.514Z [INFO] agent.auto_config: discover-aws: Instance i-09cc796081995cdc1 has IPv6 2a05:d014:d9e:c303:e4d3:d281:a61d:8ebd on NetworkInterfaceId eni-0eb12a1d1acec6e61
consul[12945]: 2021-12-15T03:41:57.514Z [INFO] agent.auto_config: discover-aws: Instance i-0cc65f132aaa635ba has IPv6 2a05:d014:d9e:c304:fc9f:38cd:a734:5022 on NetworkInterfaceId eni-0f8a76deed0c941fa
consul[12945]: 2021-12-15T03:41:57.514Z [INFO] agent.auto_config: discover-aws: Instance i-09f5a19c8ee3f55cb has IPv6 2a05:d014:d9e:c305:b0bc:d053:f019:ed77 on NetworkInterfaceId eni-06c9484734c3d2e4d
consul[12945]: 2021-12-15T03:41:57.514Z [WARN] agent.auto_config: error splitting host address into IP and port: address=2a05:d014:d9e:c303:e4d3:d281:a61d:8ebd error="address 2a05:d014:d9e:c303:e4d3:d281:a61d:8ebd: too many colons in address"
consul[12945]: 2021-12-15T03:41:57.514Z [WARN] agent.auto_config: error splitting host address into IP and port: address=2a05:d014:d9e:c304:fc9f:38cd:a734:5022 error="address 2a05:d014:d9e:c304:fc9f:38cd:a734:5022: too many colons in address"
consul[12945]: 2021-12-15T03:41:57.514Z [WARN] agent.auto_config: error splitting host address into IP and port: address=2a05:d014:d9e:c305:b0bc:d053:f019:ed77 error="address 2a05:d014:d9e:c305:b0bc:d053:f019:ed77: too many colons in address"
consul[12945]: 2021-12-15T03:41:57.514Z [ERROR] agent.auto_config: no auto-encrypt server addresses available for use
```