Chopper generator is wrong when generating nullable @PartFile field

[luis901101]

Use case:
I have a photo field that it needs to be nullable which means user wants to remove the profile photo.

The chopper request definition:

@Post(
    path: "profile",
    headers: {
      'content-type': 'multipart/form-data'
    },
  )
  @multipart
  Future<Response> updateProfile({
    @Part(Params.NAME) String? fullName,
    @Part(Params.PHONE) String? phone,
    @Part(Params.EMAIL) String? email,
    @PartFile(Params.FILE) MultipartFile? photo
  });

Then, after flutter pub run build_runner build:

@override
  Future<Response<dynamic>> updateProfile(
      {String? fullName,
      String? phone,
      String? email,
      MultipartFile? photo}) {
    final $url = '/profile';
    final $headers = {
      'content-type': 'multipart/form-data',
    };

    final $parts = <PartValue>[
      PartValue<String?>('name', fullName),
      PartValue<String?>('phone', phone),
      PartValue<String?>('email', email),
      PartValueFile<MultipartFile>('file', photo)
    ];
    final $request = Request('POST', $url, client.baseUrl,
        parts: $parts, multipart: true, headers: $headers);
    return client.send<dynamic, dynamic>($request);
  }

The thing here is that generated code PartValueFile<MultipartFile>('file', photo) is not according to the @PartFile(Params.FILE) MultipartFile? photo definition which is nullable. It should be PartValueFile<MultipartFile?>('file', photo)