[BUG] MultipartFile not show input file on swagger

## Information

- **Version:** 6.126.1
- Packages:
    "@tsed/common": "6.126.1",
    "@tsed/core": "6.126.1",
    "@tsed/exceptions": "6.126.1",
    "@tsed/json-mapper": "6.126.1",
    "@tsed/platform-express": "6.126.1",
    "@tsed/swagger": "6.126.1",
    "@tsed/typeorm": "6.126.1",

## Example

```ts
import { MultipartFile, Controller } from "@tsed/common";
 @Post('/upload/avatar')
  async uploadAvatar(
        @Req() req: Request,
        @Res() res: Response,
        @MultipartFile('file') file: Express.Multer.File,
    ) {
}
```

## Acceptance criteria
See image, no input file
<img width="1026" alt="Screen Shot 2022-08-15 at 13 44 03" src="https://user-images.githubusercontent.com/67777599/184589093-15c157ec-ae39-43a1-8c75-87bb4abd64ce.png">

