[BUG] [angular-typescript] Incorrect JSON object in HTTP request multipart form data

Created by: Beaurpi

Hi there,

I've figured out that there is an issue with the code generated, when using a multipart/form-data object. Declare a POST method with the following requestBody:

'/test/upload':
post:
requestBody:
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                name:
                  type: string
                title:
                  type: object
                  properties:
                    en:
                      type: string
                    fr:
                      type: string
                fileName:
                  type: string
                  format: binary

It's related to the generated code in angular typescript. in the generation command line i'm using the following: -g typescript-angular

the generated service will have a good signature: public uploadFile(id: string, name?: string, title?: UploadTitle, .....

But the HTTP post, will not pass a JSON for the parameter 'TITLE'. It will actually encode the object as string. As a result the 'title' parameter will be

-----------------------------8302951520691
Content-Disposition: form-data; name="title"

[object: Object]

Instead the parameter title should be

-----------------------------8302951520691
Content-Disposition: form-data; name="title"

{ en: 'sometext', fr: 'loren ipsum' }