[BUG][Scala][scala-sttp] Client does not generate decoders when using reusable enums

Bug Report Checklist

• [ X] Have you provided a full/minimal spec to reproduce the issue?
• [ X] Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• [ X] Have you searched for related issues/PRs?
• [ X] What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

I have the following openapi file:

components:
  schemas:
    Order:
      type: string
      enum:
        - asc
        - desc
    ErrorRecord:
      type: object
      properties:
        message:
          type: string
    PaginationInfo:
      type: object
      properties:
        sortBy:
          type: string
        order:
          $ref: '#/components/schemas/Order'
        page:
          type: integer
        pageSize:
          type: integer

When I generate an open-api client, the Order component does not get generated with JSON decoders, causing a compile error

openapi-generator version

5.4.0

Start with the provided OpenAPI schema and the scala-sttp generator at version 5.4.0, then generate the client and inspect the reusable Order enum output. Confirm that its JSON decoder is missing and that the generated client fails to compile; done means the enum has the expected decoder and the client compiles.