Generated openAPI shows example in application/json instead of specified text/plain

[jiramares]

Describe the bug
Specifying text/plain media type for response causes openAPI shows response example in wrong media type (stilll uses application/json).

To Reproduce
Following endpoint specifies response media type to text/plain:

val ep2 = Endpoint(RoutePattern.GET / "greeting" / string("name"))
    .outCodec(HttpCodec.content[Greeting](MediaType.text.plain))

and generated openAPI shows response as (the media type is right text/plain):

{
  "msg": "string"
}

Expected behaviour
The response example should be:

string

Dependencies:

    "dev.zio" %% "zio" % "2.1.9",
    "dev.zio" %% "zio-http" % "3.0.1"
    "dev.zio" %% "zio-schema" % "1.4.1"

[jiramares]

The same is also true for error channel:

val ep5 = Endpoint(RoutePattern.GET / "greeting3" / nameParam / "exclamation" / boolParam)
        .copy(error = HttpCodec.content[Greeting](MediaType.text.plain) ++ HttpCodec.status(Status.NotFound))
        .outCodec(HttpCodec.content[Greeting](MediaType.text.plain))

the example error response is

{
  "msg": "string"
}

not plain text

string