[BUG] The OpenAPIDocsInterpreter does not generate a correct YAML for a Tapir endpoint with oneOf output

Tapir version: 1.7.3

Scala version: 3.3.0 and 2.13.x

Describe the bug
The OpenAPIDocsInterpreter does not generate a correct YAML for a Tapir endpoint that uses oneOf in its output.

How to reproduce?

Minimal reproduction:

//> using scala 3.3
//> using lib "com.softwaremill.sttp.tapir::tapir-core:1.7.3"
//> using lib "com.softwaremill.sttp.tapir::tapir-json-circe:1.7.3"
//> using lib "com.softwaremill.sttp.tapir::tapir-openapi-docs:1.7.3"
//> using lib "com.softwaremill.sttp.apispec::openapi-circe-yaml:0.6.0"

import io.circe.generic.auto.*
import sttp.apispec.openapi.OpenAPI
import sttp.apispec.openapi.circe.yaml.*
import sttp.tapir.*
import sttp.tapir.docs.openapi.OpenAPIDocsInterpreter
import sttp.tapir.json.circe.*
import sttp.tapir.generic.auto.*

object TapirBugExample extends App:
  case class First(value: Int)
  case class Second(value: String)

  val endpointOutput =
    oneOf(
      oneOfVariant(jsonBody[First]),
      oneOfVariant(jsonBody[Second])
    )

  val testEndpoint =
    endpoint
      .in("demo")
      .out(endpointOutput)

  val docs: OpenAPI = OpenAPIDocsInterpreter().toOpenAPI(testEndpoint, "test", "1.0").openapi("3.0.3")

  println(docs.toYaml3_0_3)

This code, when run with scala-cli, produces the following output:

openapi: 3.0.3
info:
  title: test
  version: '1.0'
paths:
  /demo:
    get:
      operationId: getDemo
      responses:
        '200':
          description: ''
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Second'
components:
  schemas:
    First:
      required:
      - value
      type: object
      properties:
        value:
          type: integer
          format: int32
    Second:
      required:
      - value
      type: object
      properties:
        value:
          type: string

The First type is missing from the responses section of the /demo path.

Start with the minimal Scala reproduction and the OpenAPIDocsInterpreter().toOpenAPI entry point, using the Tapir 1.7.3 dependencies shown. Compare the generated YAML for the oneOf output with the expected response schema; done means the /demo response represents both First and Second rather than only Second.