[BUG][JAVA] oneOf discriminator type string with enum ignores model prefix and suffix names

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

Using version 7.00-beta, when you try to generate oneOf with discriminator property referencing to enum, then everything works fine, but once you add generate model suffix using modelNameSuffix, compilation is failing, because suffix is not added because parent model is using enum name without suffix.

openapi-generator version

7.0.0-beta

OpenAPI declaration file content or url

openapi: 3.0.3
info:
  title: transactions
  description: transactions
  version: 1.0.0

tags:
  - name: transactions

paths:
  /v1/transactions:
    post:
      tags:
        - transactions
      operationId: requestTransaction
      summary: Create transaction
      requestBody:
        description: transaction
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/TransactionCreateRequest"
      responses:
        200:
          description: Created transaction
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/TransactionCreateRequest"
                
components:
  schemas:
    TransactionCreateRequest:
      type: object
      required:
        - assets
      properties:
        assets:
          $ref: "#/components/schemas/TransactionAssets"

    TransactionAssets:
      type: object
      discriminator:
        propertyName: type
        mapping:
          CASH: "#/components/schemas/TransactionCashAssets"
          ITEMS: "#/components/schemas/TransactionItemsAssets"
      oneOf:
        - $ref: "#/components/schemas/TransactionCashAssets"
        - $ref: "#/components/schemas/TransactionItemsAssets"
      properties:
        type:
          $ref: "#/components/schemas/TransactionAssetsType"

    TransactionCashAssets:
      type: object
      required:
        - type
        - amount
      properties:
        type:
          $ref: "#/components/schemas/TransactionAssetsType"
        amount:
          type: number

    TransactionItemsAssets:
      type: object
      required:
        - type
        - items
      properties:
        type:
          $ref: "#/components/schemas/TransactionAssetsType"
        items:
          type: number

    TransactionAssetsType:
      type: string
      enum:
        - CASH
        - ITEMS

Generation Details

                    <execution>
                        <id>client</id>
                        <phase>none</phase>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <inputSpec>${project.basedir}/../api.yaml</inputSpec>

                            <generatorName>java-enhanced</generatorName>
                            <library>webclient</library>

                            <modelNameSuffix>Dto</modelNameSuffix>

                            <generateApis>true</generateApis>
                            <generateApiTests>false</generateApiTests>
                            <generateModels>true</generateModels>
                            <generateModelTests>false</generateModelTests>

                            <configOptions>
                                <oas3>true</oas3>
                                <java7>true</java7>

                                <aotHintsEnabled>true</aotHintsEnabled>

                                <dateLibrary>java8-localdatetime</dateLibrary>
                                <interfaceOnly>true</interfaceOnly>

                                <useJakartaEe>true</useJakartaEe>
                                <useSpringBoot3>true</useSpringBoot3>

                                <useTags>true</useTags>

                                <delegatePattern>true</delegatePattern>

                                <!--suppress UnresolvedMavenProperty -->
                                <additionalModelTypeAnnotations>@lombok.Builder @lombok.AllArgsConstructor
                                </additionalModelTypeAnnotations>
                            </configOptions>
                        </configuration>
                    </execution>

Steps to reproduce

mvn clean install

Receive error:
[41,12] cannot find symbol [ERROR] symbol: class TransactionAssetsType [ERROR] location: interface com.steam.trading.api.transactions.dto.TransactionAssetsDto

Related issues/PRs

Feature was added by https://github.com/OpenAPITools/openapi-generator/issues/12412

Suggest a fix

Add logic to add suffix and prefix in templates when using enum discriminator

Start with the Java enhanced generator and its templates, using the provided OpenAPI declaration and modelNameSuffix=Dto configuration to reproduce the failure. Run mvn clean install and confirm that the generated TransactionAssetsDto refers to the suffixed enum type and compiles successfully.