[BUG][typescript-angular] Tagged unions not working as expected

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?
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Description

When generating a typescript-angular client with taggedUnion an empty interface is generated where a union is expected

openapi-generator version

7.12.0

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  title: OpenAPI definition
  version: v0
paths:
  /api/test/zoo:
    get:
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Zoo'
components:
  schemas:
    Animal:
      type: object
      discriminator:
        propertyName: type
      properties:
        type:
          type: string
      required:
        - type
    Cat:
      allOf:
        - $ref: '#/components/schemas/Animal'
        - type: object
          properties:
            purrFrequency:
              type: integer
              format: int32
    Dog:
      allOf:
        - $ref: '#/components/schemas/Animal'
        - type: object
          properties:
            barkVolume:
              type: integer
              format: int32
    Zoo:
      type: array
      items:
        oneOf:
          - $ref: '#/components/schemas/Cat'
          - $ref: '#/components/schemas/Dog'

Generation Details

openapi-generator-cli generate -i ./allOf_composition_discriminator_collection.yaml -g typescript-angular -o ./out --additional-properties=taggedUnion=true

Steps to reproduce

Created a failing test.

In essence - the expected output in /model/zooInner.ts should contain:

export type ZooInner = Cat | Dog;

But in reality contains:

export interface ZooInner { 
}

Start with the linked TypeScriptAngularClientCodegenTest.java failing test and reproduce the generation command using the provided OpenAPI declaration. Inspect the generated /model/zooInner.ts output for the tagged union case. Done means it declares ZooInner as Cat | Dog rather than an empty interface, with the test passing.