Adding complex object to request().field() method

## Describe the bug

**Node.js version:** 18.18.2

**OS version:** macOS Sonoma 14.4

**Description:**

When adding complex object to field() method, the documentation says to use it like this. #759

.field('complex_object', '{"attribute": "value"}', {contentType: 'application/json'})

With this solution, I got an error.

Expected 1-2 arguments, but got 3.ts(2554)

@types/supertest 6.0.2
supertest 7.0.0
typescript 5.4.5

## Actual behavior

```
await request(app)
.post('/test')
.field('myObject', JSON.stringify({ key1: 'key1', key2: 'key2' }), { contentType: 'application/json' })
.attach('attachments', path.join(__dirname, 'image.png'))
.expect(200)
```

## Expected behavior

Test success without an error.

## Code to reproduce

## Checklist

- [x] I have searched through GitHub issues for similar issues.
- [x] I have completely read through the README and documentation.
- [ ] I have tested my code with the latest version of Node.js and this package and confirmed it is still not working.