fix: build in web environment

[lightrabbit]

screen_capturer-0.1.5/lib/src/screen_capturer.dart:23:62: Error: Too few positional arguments: 1 required, 0 given.
      _systemScreenCapturer = SystemScreenCapturerImplWindows();
lib/src/system_screen_capturer_impl_windows_noop.dart:6:3: Context: Found this candidate, but the arguments don't match.
  SystemScreenCapturerImplWindows(MethodChannel methodChannel);

fix: build in web

[lijy91]

LGTM