`omitempty` is not appropriate for `explode` field

[auzhva]

According to OpenAPI specs, explode field defaults to true in case of style: form and to false otherwise.

But in Gnostic model follows the standard "false by default" and its outputting false value even in case if it's not by default.

This means that if I read below spec by gnostic:

{
  "openapi": "3.1.1",
  "paths": {
    "/users": {
      "get": {
        "parameters": [
          {
            "name": "id",
            "in": "query",
            "explode": false,
            "schema": {
              "type": "integer"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "ok"
          }
        }
      }
    }
  }
}

And output it back, it will write:

{
  "openapi": "3.1.1",
  "paths": {
    "/users": {
      "get": {
        "parameters": [
          {
            "name": "id",
            "in": "query",
            "schema": {
              "type": "integer"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "ok"
          }
        }
      }
    }
  }
}

Which is not the same thing.