[BUG] spring generator using maven plugin generates correct code, while cli/gradle generates wrong code

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?
• [Optional] Bounty to sponsor the fix (example)

Description

I have a simple sample spec. When invoking the generator from maven plugin, code is generated as expected. But both gradle plugin and cli generate a different code.

on the generated interface com.example.api.DefaultApi, when running from Gradle/CLI, this code is generated:

    ResponseEntity<InlineResponse200> getGreetingsMessage(ServerWebExchange exchange);

Which is wrong as it is using reactive classes, which are disabled on the config file.

When using maven plugin, the following code is generated instead:

    ResponseEntity<InlineResponse200> getGreetingsMessage();

which seems to be the correct code.

openapi-generator version

4.3.1

OpenAPI declaration file content or url

openapi: '3.0.3'
info:
  title: 'Greetings API'
  version: '1.0.0'
paths:
  /api/v1/greetings:
    get:
      operationId: getGreetingsMessage
      responses:
        200:
          description: 'A greetings message'
          content:
            application/json:
              schema:
                type: object
                properties:
                  message:
                    type: string

Command line used for generation

openapi-generator generate \
    --input-spec spec.yaml \
    --config config.json \
    --generator-name spring \
    --output . \
    --invoker-package com.example \
    --api-package com.example.api \
    --model-package com.example.model

Config file used for generation

{
  "useTags": "true",
  "interfaceOnly": "true",
  "hideGenerationTimestamp": "true",
  "sourceFolder": "src/gen/java",
  "java8": "true",
  "library": "spring-boot",
  "dateLibrary": "java8",
  "reactive": "false",
  "useOptional": "true",
  "useBeanValidation": "true",
  "skipDefaultInterface": "true"
}

Steps to reproduce

copy both spec.yaml and config.json to a folder and run open-api-generator-cli as described above.

Related issues/PRs

No related issues I could find.

Suggest a fix

Start with spec.yaml and config.json, then trace the spring generator path used by the CLI and Gradle plugin, comparing it with the Maven plugin behavior. Reproduce the generation command and verify that reactive=false produces DefaultApi.getGreetingsMessage() without ServerWebExchange.