[BUG] default values for references enums are not generated correctly

Created by: robbertvanwaveren

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?
[Optional] Sponsorship to speed up the bug fix or feature request (example)

Seen this bug in Java client generation but I think its broken for multiple languages.

Description

properties that set a default but references an enum type using allOf results in incompilable java client code.

openapi-generator version

regression since 6.3.0 (probably since #14130 was merged)

OpenAPI declaration file content or url

openapi: 3.0.2
info:
  title: Bug
  version: 0.0.1
paths:
  /test:
    post:
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                test:
                  allOf:
                    - $ref: '#/components/schemas/TestEnum'
                  default: Bar
      responses:
        '200':
          description: Ok
components:
  schemas:
    TestEnum:
      enum:
        - Foo
        - Bar
      type: string

Generation Details

openapi-generator-cli generate -i default-for-referenced-enum.yaml -g java -o enum-issue

results in TestPostRequest.java with line 54 being:

private TestEnum test = Bar;

instead of

private TestEnum test = TestEnum.BAR;

Steps to reproduce

see Generation Details

Related issues/PRs

regression since 6.3.0 (probably since #14130 was merged)

Suggest a fix

See linked PR #14692