[FEATURE] _nodes/settings misses the plugins field

[Jakob3xD]

Is your feature request related to a problem?

When doing the spec test against the Opensearch started by the opensearch-go project,
I noticed the test complaining about a missing field plugins.

curl https://localhost:9200/_nodes/settings -k -u admin

{
  "_nodes": {
    "total": 1,
    "successful": 1,
    "failed": 0
  },
  "cluster_name": "docker-cluster",
  "nodes": {
    "6fYrI3t8QWeUjBzYb2t05w": {
      "name": "60bf0b26a1cf",
      "transport_address": "172.19.0.2:9300",
      "host": "172.19.0.2",
      "ip": "172.19.0.2",
      "version": "2.15.0",
      "build_type": "tar",
      "build_hash": "61dbcd0795c9bfe9b81e5762175414bc38bbcadf",
      "roles": [
        "cluster_manager",
        "data",
        "ingest",
        "remote_cluster_client"
      ],
      "attributes": {
        "shard_indexing_pressure_enabled": "true"
      },
      "settings": {
        "cluster": {
          "name": "docker-cluster"
        },
        "node": {
          "attr": {
            "shard_indexing_pressure_enabled": "true"
          },
          "max_local_storage_nodes": "3",
          "name": "60bf0b26a1cf"
        },
        "path": {
          "logs": "/usr/share/opensearch/logs",
          "home": "/usr/share/opensearch",
          "repo": [
            "/usr/share/opensearch/mnt"
          ]
        },
        "discovery": {
          "type": "single-node"
        },
        "plugins": {
          "index_state_management": {
            "job_interval": "1"
          }
        },
        "client": {
          "type": "node"
        },
        "http": {
          "compression": "false",
          "type": "org.opensearch.security.http.SecurityHttpServerTransport",
          "type.default": "netty4"
        },
        "index": {
          "store": {
            "hybrid": {
              "mmap": {
                "extensions": [
                  "nvd",
                  "dvd",
                  "tim",
                  "tip",
                  "dim",
                  "kdd",
                  "kdi",
                  "cfs",
                  "doc",
                  "vec",
                  "vex"
                ]
              }
            }
          }
        },
        "bootstrap": {
          "memory_lock": "true"
        },
        "transport": {
          "type": "org.opensearch.security.ssl.http.netty.SecuritySSLNettyTransport",
          "type.default": "netty4"
        },
        "network": {
          "host": "0.0.0.0"
        }
      }
    }
  }
}

What solution would you like?

Add plugins to NodeInfoSettings in the spec/schemas/nodes.info.yaml file.
I would guess the type should be map[string]any. Meaning:

node.info:NodeInfoSettings:
    type: object
    properties:
        plugins:
            $ref: '#/components/schemas/NodeInfoSettingsPlugins'
node.info:NodeInfoSettingsPlugins:
    type: object
    additionalProperties:
        $ref: '_common.yaml#/components/schemas/FieldValue'