[BUG] [SPRING] OpenAPI generated DTO interface doesn't include required properties other than discriminator

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 objects for polymorphism, only the discrminator property is actually included, other properties are ignored from the interface.
For example given the example shown later on, I would expect the interface to look like:

public interface CoreSchema {
    public String getDiscriminatorProperty();
    public String getAnotherValue();
}

However what I get is just:

public interface CoreSchema {
    public String getDiscriminatorProperty();
}

with getAnotherValue() missing. The subclass implementations are all correct and do contain this getter however, so the code does technically work but need to use instanceof (in Java) to be able to access the anotherValue string. This shouldn't be necessary and should be accessible on the incoming interface.

openapi-generator version

7.4.0

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: Test Integration
  description: Test API spec for Gradle generation plugin
  version: v1
tags:
  - name: test
    description: Methods relating to testing API spec for Gradle generation plugin
paths:
  /pattern-validation:
    post:
      tags:
        - test
      description: Returns body
      operationId: patternValidationPost
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CoreSchema'
        required: true
      responses:
        '200':
          description: Test requested
        '400':
          description: Bad request
components:
  schemas:
    CoreSchema:
      type: object
      properties:
        discriminatorProperty:
          type: string
        anotherValue:
          type: string
      required:
        - discriminatorProperty
        - anotherValue
      discriminator:
        propertyName: discriminatorProperty
        mapping:
          ONE: '#/components/schemas/OneSchema'
          TWO: '#/components/schemas/TwoSchema'
      oneOf:
        - $ref: '#/components/schemas/OneSchema'
        - $ref: '#/components/schemas/TwoSchema'
    OneSchema:
      type: object
      required:
        - anotherValue
      properties:
        anotherValue:
          type: string
          pattern: '^\d{3}$'
    TwoSchema:
      type: object
      required:
        - anotherValue
      properties:
        anotherValue:
          type: string
          pattern: '^\d{8}$'
servers:
  - url: 'http://localhost:8080'

Generation Details

Spring Generator, via Gradle plugin

Steps to reproduce

Create an OpenAPI spec with polymorphic components described similar to above structure
Run generator for Spring
Check created DTO classes

Related issues/PRs

Unsure

Suggest a fix

Unsure

Start by running the Spring generator through the Gradle plugin with the OpenAPI declaration provided in the issue, then inspect the generated DTO interfaces and subclass implementations. The reproduction is complete when the CoreSchema interface exposes getters for both discriminatorProperty and anotherValue without requiring instanceof access.