[BUG][JAVA][SPRING] missing JsonValue import if allOf used with 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

Missing import means that code does not compile...

openapi-generator version

6.3.0-snapshot, 6.2.1

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: Test
  description: 'Test'
  version: v2.0

tags:
  - name: Test

paths:
  /test:
    get:
      tags:
        - Test
      description: Test
      operationId: test
      responses:
        '204':
          description: ''
    
components:
  schemas:
    SimulationEvent:
      required:
        - eventTime
      type: object
      properties:
        eventTime:
          type: integer
          format: int64
      discriminator:
        propertyName: type
    TransactionEvent:
      type: object
      properties:
        transactionType:
          type: string
          enum:
            - purchase
            - withdraw
            - refund
            - load
      allOf:
        - $ref: '#/components/schemas/SimulationEvent'
    

Generation Details

docker run --rm --workdir /github/workspace -v $(pwd):/github/workspace openapitools/openapi-generator-cli:v6.2.1 generate -g spring -o /github/workspace/spring-client -i /github/workspace/contract.yml -p groupId=co.test,basePackage=co.test.v2.server.config,basePackage=co.test.v2.server,apiPackage=co.test.v2.server,invokerPackage=co.test.v2.server.invoker,modelPackage=co.test.v2.server.models,library=spring-boot,artifactId=test-v2-server,documentationProvider=none,useSwaggerUI=false,interfaceOnly=true,snapshotVersion=true

Steps to reproduce

1. Save the contract above into file contract.yml
2. Run the docker command above
3. open spring-client/src/main/java/co/test/v2/server/models/TransactionEvent.java
4. Verify that @JsonValue is used in code but it is not imported

Related issues/PRs

There was similar issue before https://github.com/OpenAPITools/openapi-generator/issues/11323 And I can confirm that this is similar nature issue because hasEnums is not set during generation of that class...

Suggest a fix

I dont have suggestion for a fix, but tmp workaround is to add this code on top of pojo.mustache:

{{#jackson}}
{{^hasEnums}}
import com.fasterxml.jackson.annotation.JsonValue;
{{/hasEnums}}
{{/jackson}}

As you can see I am adding import only when the hasEnums is false... Because otherwise we are risking that we will have same import twice...

Important debugging note:
If you remove discriminator from the contract above, the generation is working fine...

Start with pojo.mustache and reproduce the report using contract.yml and the documented Docker generation command. Inspect the generated TransactionEvent.java, especially the @JsonValue usage and hasEnums behavior when discriminator and allOf are present. Done means the generated Spring Java code includes the required import exactly once and compiles.