[BUG] Scala Sttp Codegen generates empty case class for named enums

Created by: acgray

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

Scala Sttp generator generates empty case class instead of enum for named (i.e., top-level) enum models.

openapi-generator version

4.3.1

OpenAPI declaration file content or url

...
components:
  schemas:
    PetType:
      enum:
      - CAT
      - DOG
      - FROG
      type: string
...

Generation Details

• Generator: scala-sttp

Suggest a fix

PR to follow