Json field OpenAPI

[fokot]

Is your feature request related to a problem? Please describe.
I have case class with Json field. I'm using Schema[Json] from zio.schema.codec.json._ to accept any json (object, number, string etc.) but in the generated OpenAPI I see that the type of json field is string. I think for this use case it would be better if the type would be json object

type: object
additionalProperties: true

Here is the code

import zio.*
import zio.http.*
import zio.http.codec.*
import zio.http.codec.PathCodec.*
import zio.http.endpoint.*
import zio.http.endpoint.openapi.*
import zio.json.{DeriveJsonDecoder, DeriveJsonEncoder, JsonDecoder, JsonEncoder}
import zio.json.ast.Json
import zio.schema.{DeriveSchema, Schema}
import zio.schema.annotation.description
import zio.schema.codec.json._


case class TestClass(
  name: String,
  json: Json
)

object TestClass {
  given Schema[TestClass] = DeriveSchema.gen[TestClass]
  given JsonDecoder[TestClass] = DeriveJsonDecoder.gen[TestClass]
  given JsonEncoder[TestClass] = DeriveJsonEncoder.gen[TestClass]
}

object Main extends ZIOAppDefault:

  val jsonFieldEndpoint =
    Endpoint(RoutePattern.GET / "json-field")
      .in[TestClass]
      .out[TestClass]

  val jsonFieldRoute = jsonFieldEndpoint.implementHandler(handler { (tc: TestClass) => ZIO.succeed(tc).debug("json-field") })

  def run: ZIO[ZIOAppArgs & Scope, Throwable, Unit] =
    for
      _ <- Console.printLine(s"Starting ZIO-HTTP server. Open http://localhost:8080/docs/openapi")
      openAPI = OpenAPIGen.fromEndpoints(
        title = "API",
        version = "1.0.0",
        jsonFieldEndpoint,
      )
      swaggerRoutes = SwaggerUI.routes(path("docs") / "openapi", openAPI)
      allRoutes = Routes(jsonFieldRoute) ++ swaggerRoutes
      process <- Server.serve(allRoutes).provide(Server.default)
    yield ()

Describe the solution you'd like
Custom handlind for Schema[Json] which will render

type: object
additionalProperties: true

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.