[BUG][JAVA] schemaMapping not working for POST requestBody

Hey!

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?
  I have tested it with 6.2.1.
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

I can't get the schemaMapping to work with a POST request where I reference a object from an external package via schemaMapping.
It works flawlessly for returning objects though. See my provided examples.

openapi-generator version

6.2.1

OpenAPI declaration file content or url

paths:
  /test/loadTest:
    get:
      tags:
        - test
      operationId: loadTest
      responses:
        200:
          description: Test object
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Test'

  /test/saveTest:
    post:
      tags:
        - test
      operationId: saveTest
      requestBody:
        description: TestToSave object
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/TestToSave'
      responses:
        201:
          description: Created

components:
  schema:
    Test:
      type: object
      description: "external Test object"

    TestToSave:
      type: object
      description: "external TestToSave object"

Generation Details

My schemaMappings maven configuration:

<schemaMappings>
    Test=my.external.test.package.model.Test,
    TestToSave=my.external.test.package.model.TestToSave,
</schemaMappings>

As you can see the saveTest(@NotNull Object body) method isn't correctly mapped to
my.external.test.package.api.model.TestToSave, even though I have set it in the schema mappings.
The weird thing is, that the schema mapping works correctly with the loadTest() method.

@ServiceInterface
@Local
public interface TestService {

    /**
     * @return my.test.package.api.model.Test
     */
    my.external.test.package.api.model.Test loadTest() throws TestUiException;

    /**
     * @param body TestToSave object
     */
    void saveTest(@NotNull Object body) throws TestUiException; // <-- should be my.external.test.package.api.model.TestToSave
}

Thanks!

Start with the supplied OpenAPI declaration and Maven schemaMappings configuration, then run generation for the Java output. Compare the generated loadTest and saveTest methods, focusing on how the requestBody schema is resolved. Done means saveTest accepts my.external.test.package.model.TestToSave instead of Object while loadTest continues to use the mapped Test type.