docker info missing swarm-mode CA configuration details

[dhiltgen]

When configured with a remote CA, the API reports this information, but it doesn't show up in the CLI, making it difficult to use the docker swarm update CLI.

Excerpt from the raw API after configuring a remote CA:

        "CAConfig": {
          "NodeCertExpiry": 7776000000000000,
          "ExternalCAs": [
            {
              "Protocol": "cfssl",
              "URL": "https://192.168.42.184:12381"
            }
          ]
        },

However the CLI does not report this:

Swarm: active
 NodeID: 5f8v5um0aug2z9f6ge5zycek7
 Is Manager: true
 ClusterID: 3mkb5ig7mr6sprc2pxme5ordl
 Managers: 1
 Nodes: 1
 Orchestration:
  Task History Retention Limit: 10
 Raft:
  Snapshot interval: 10000
  Heartbeat tick: 1
  Election tick: 3
 Dispatcher:
  Heartbeat period: 5 seconds
 CA configuration:
  Expiry duration: 3 months
 Node Address: 192.168.42.184

[yongtang]

@dhiltgen I created a pull request #25204 to add the external CA to the output of docker info, e.g.,:

 CA configuration:
  Expiry duration: 3 months
  External CAs:
    cfssl: https://172.17.0.2:8888

Please let me know if there are any issues.