[lang php] object in query param sent as json string instead associative array

Description

Via https://editor.swagger.io/ generated correct request with multidemensional array settings:

settings[app_info][app_id]=123&settings[app_info][app_hash]=321

But via PHP generated client generated request:

/system/addSession?session=sxfgd&settings=%7B%0A%20%20%20%20%22settings%22%3A%20%7B%0A%20%20%20%20%20%20%20%20%22app_info%22%3A%20%7B%0A%20%20%20%20%20%20%20%20%20%20%20%20%22app_id%22%3A%20123%2C%0A%20%20%20%20%20%20%20%20%20%20%20%20%22app_hash%22%3A%20%22321%22%0A%20%20%20%20%20%20%20%20%7D%0A%20%20%20%20%7D%0A%7D

/system/addSession?session=sxfgd&settings={
    "settings": {
        "app_info": {
            "app_id": 123,
            "app_hash": "321"
        }
    }
}

            $ai = new AppInfo();
            $ai->setAppId($event->getApplication()->api_id);
            $ai->setAppHash($event->getApplication()->api_hash);

            $ss = new SessionSettings();
            $ss->setAppInfo($ai);

            $settings = new Settings();
            $settings->setSettings($ss);

            $getSessionListResponse = $apiInstance->addSession($event->getSession(), $settings);

session param is string contains json object. This is not correct request.

Swagger-codegen version

swagger-codegen-cli-3.0.22.jar

Swagger declaration file content or url

openapi: 3.0.1
info:
  title:

  version:

servers:
- url:

paths:
  /system/addSession:
    get:
      parameters:
      - name: session
        in: query
        description: Session name
        required: true
        schema:
          type: string
      - name: settings
        in: query
        description: Settings
        required: false
        schema:
          $ref: '#/components/schemas/settings'
      responses:
        "200":
          description: successful operation

components:
  schemas:
    AppInfo:
      type: object
      properties:
        app_id:
          type: integer
          description: App api_id
        app_hash:
          type: string
          description: App api_hash
    settings:
      type: object
      properties:
        settings:
          $ref: '#/components/schemas/SessionSettings'
    SessionSettings:
      type: object
      properties:
        app_info:
          $ref: '#/components/schemas/AppInfo'

Command line used for generation

docker run --rm -v ${PWD}:/local -w /local openjdk java -jar swagger-codegen-cli.jar generate --input-spec /local/openapi.yaml --lang php --output /local/out/ -c /local/openapi-codegen-php.json

Steps to reproduce

Related issues/PRs

Suggest a fix/enhancement

Start by reproducing the generated PHP client request from the supplied openapi.yaml with swagger-codegen-cli-3.0.22.jar, then inspect the generated addSession call and its query serialization. Compare the object-valued settings parameter with the Swagger Editor request; done means nested settings are sent as associative query parameters rather than a JSON string.