[Typescript Angular] oneOf with schemas 7.0.0-beta "Could not process model"

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)

Description

When generating the MODELS/Services using Open Api Generator 7.0.0-beta i get the following error:

Exception in thread "main" java.lang.RuntimeException: Could not process model 'Dummy'.Please make sure that your schema is correct!
        at org.openapitools.codegen.DefaultGenerator.generateModels(DefaultGenerator.java:529)
        at org.openapitools.codegen.DefaultGenerator.generate(DefaultGenerator.java:950)
        at org.openapitools.codegen.cmd.Generate.execute(Generate.java:487)
        at org.openapitools.codegen.cmd.OpenApiGeneratorCommand.run(OpenApiGeneratorCommand.java:32)
        at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:66)

When using 6.6.0, the Models and Services where generated successfully

openapi-generator version

7.0.0-beta, it did work with 6.6.0

OpenAPI declaration file content or url

openapi: 3.0.3
info:
  title: testy
  version: 1.0.1
servers:
  - description: Dummy localhost server
    url: 'http://localhost:8080/dummy'
tags:
  - description: 'Dummy Operation'
    name: DummyOpertaion
paths:
  '/v1/dummy':
    get:
      operationId: DummyOperation
      responses:
        '200':
          content:
            application/json:
              schema:
                description: Response of the Dummy operation.
                properties:
                  testy: &ref_1
                    oneOf:
                      - properties:
                          dummy:
                            type: string
                      - properties:
                          dummy2:
                            type: number
                    title: Dummy
                    type: object
                  notWorkingTesty:
                    $ref: '#/components/schemas/Dummy'
                type: object
          description: 'Testy'
components:
  schemas:
    Dummy: *ref_1

following "same" yaml (without shortcut references) is working fine:

openapi: 3.0.3
info:
  title: testy
  version: 1.0.1
servers:
  - description: Dummy localhost server
    url: 'http://localhost:8080/dummy'
tags:
  - description: 'Dummy Operation'
    name: DummyOpertaion
paths:
  '/v1/dummy':
    get:
      operationId: DummyOperation
      responses:
        '200':
          content:
            application/json:
              schema:
                description: Response of the Dummy operation.
                properties:
                  testy:
                    $ref: '#/components/schemas/Dummy'
                  notWorkingTesty:
                    $ref: '#/components/schemas/Dummy'
                type: object
          description: 'Testy'
components:
  schemas:
    Dummy:
      oneOf:
        - properties:
            dummy:
              type: string
        - properties:
            dummy2:
              type: number

Generation Details

Running the following Command:

java -jar C:\git\fip\frontend\libs\core\api\dist\openapi-generator-cli-7.0.0-beta.jar 
    generate 
    -g typescript-angular 
    -i C:\git\fip\frontend\libs\core\api\src\lib\test\original.yaml 
    -o C:\git\fip\frontend\libs\core\api\src\lib\test 
    --generate-alias-as-model 
    --config C:\git\fip\frontend\libs\core\api\generate\test-config-options.json

with the following options (test-config-options.json)

{
  "ngVersion": "16.1.1",
  "configurationPrefix": "Test",
  "apiModulePrefix": "Test",
  "modelSuffix": "Test"
}

Steps to reproduce

Command, YAML and Options already declared

Related issues/PRs

Nothing found

Suggest a fix

Run the supplied openapi-generator command with the anchored and expanded YAML examples, comparing 7.0.0-beta with 6.6.0. Start from the reported path through DefaultGenerator.java, Generate.java, OpenApiGeneratorCommand.java, and OpenAPIGenerator.java. Done means typescript-angular models and services generate successfully for the anchored oneOf schema.