[BUG][SPRING]compilation errors due to different request body type in api and apiDelegate files

Created by: anuhyapolisetti

Bug Report Checklist

Have you provided a full/minimal spec to reproduce the issue?
Have you validated the input using an OpenAPI validator (example)?
What's the version of OpenAPI Generator used?
Have you search for related issues/PRs?
What's the actual output vs expected output?
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Description

We have encountered this problem generated Api and ApiDelegate files have different request body types (Resource/MultipartFile), which is resulting in compilation errors.

Issue seemed to have addressed in v4.0.0-beta3 version, but issue still persists when we tried with the cli version of v4.0.0-beta3.

openapi-generator version

v4.0.2

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: testapp
  version: 0.0.1
servers:
  - url: 'http://localhost:8081/api'
    description: Development server
paths:
  '/foo':
    post:
      operationId: foo
      requestBody:
        content:
          image/png:
            schema:
              type: string
              format: binary
      responses:
        default:
          description: successful operation

Command line used for generation

java -jar openapi-generator-cli.jar generate -g spring -i api.yml -o ./out --additional-properties delegatePattern=true

Steps to reproduce

Run the command above with provided api.yml.
Open out/src/main/java/org/openapitools/api/FooApi.java, look at generated foo method

    default ResponseEntity<Void> foo(@ApiParam(value = ""  )  @Valid @RequestBody Resource body) {
        return getDelegate().foo(body);
    }

Open out/src/main/java/org/openapitools/api/FooApiDelegate.java, look at generated apiDelegate method

    default ResponseEntity<Void> foo(MultipartFile body) {
        return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
    }

foo from FooApiDelegate consumes MultipartFile whereas FooApi passes Resource as request body type.

Related issues/PRs

https://github.com/OpenAPITools/openapi-generator/pull/2271

Issue seemed to have addressed in v4.0.0-beta3 version per above PR, but issue still persists when we tried with the cli version of v4.0.0-beta3.

https://github.com/OpenAPITools/openapi-generator/issues/2191

Suggest a fix

Use either Multipartfile or Resource in both api and apidelegate