Code samples do not generate parameters for multipart/form-data

 When doing this

```
requestBody:
    content:
      multipart/form-data:
```

Instead of this

```
requestBody:
    content:
      application/json:
```

Specified fields from the schema are not generated in the code samples

E.g. all I get is this, with no fields:

```
curl --request POST \
  --url $URL \
  --header 'content-type: multipart/form-data'
```