add ofnNoChangeDir to make desktop consistent for windows

[Tokenyet]

Before this changes, If we used pickFiles on Windows, the current directory would be changed. And the behavior is inconsistent with Linux and Macos, that those never modify current directory. Issue: https://github.com/miguelpruivo/flutter_file_picker/issues/804

For example (from example):

void _pickFiles() async {
    _resetState();
    try {
      _directoryPath = null;
      print(Directory.current.path);
      _paths = (await FilePicker.platform.pickFiles(
        type: _pickingType,
        allowMultiple: _multiPick,
        onFileLoading: (FilePickerStatus status) => print(status),
        allowedExtensions: (_extension?.isNotEmpty ?? false)
            ? _extension?.replaceAll(' ', '').split(',')
            : null,
      ))
          ?.files;
      print(Directory.current.path);
    } on PlatformException catch (e) {
      _logException('Unsupported operation' + e.toString());
    } catch (e) {
      _logException(e.toString());
    }
    if (!mounted) return;
    setState(() {
      _isLoading = false;
      _fileName =
          _paths != null ? _paths!.map((e) => e.name).toString() : '...';
      _userAborted = _paths == null;
    });
  }

Will output: (If I select file from C)

C:\flutter_picker_file\example
C:\

So I add the OFN_NOCHANGEDIR flag to prevent current directory from changing by default on Windows. Reference here.

Then using the sample code will output:

C:\flutter_picker_file\example
C:\flutter_picker_file\example

This make the same logic as MacOS and Linux.

[miguelpruivo]

@philenius can you take a look?

[miguelpruivo]

@Tokenyet would you mind to also update the pubspec and changelog?

Thank you!

[Tokenyet]

@Tokenyet would you mind to also update the pubspec and changelog?

Thank you!

Done! I think It's more like a bug fix rather than a new feature. If there is any problem, please Iet me know.

[arthas1888]

I have the same problem

[philenius]

hey @Tokenyet, I'm sorry that I wasn't active last year when you initially created this PR. Thank you for your input. I included your changes in #1256 and gave you credit in our CHANGELOG.md. Thanks again for pointing me in the right direction and sorry for the delay.