fix: Handle selecting files and folders for patch options correctly

[Francesco146]

closes #1703

[TheAabedKhan]

I am out of town right now. Wait for around 15 hours please.

[TheAabedKhan]

Use switch-case block instead of Map as it is potentially faster when dealing with a small, fixed set of cases due to compile-time optimizations.

switch (selection) {
  case 'file':
    final FilePickerResult? result =
        await FilePicker.platform.pickFiles();
    if (result == null) {
      return;
    }
    controller.text = result.files.single.path!;
    widget.onChanged(controller.text);
    break;
  case 'folder':
    final String? result =
        await FilePicker.platform.getDirectoryPath();
    if (result == null) {
      return;
    }
    controller.text = result;
    widget.onChanged(controller.text);
    break;
  case 'remove':
    widget.removeValue!();
    break;
  case 'null':
    controller.text = '';
    widget.onChanged(null);
    break;
}

[Francesco146]

will do within 10h

[kitadai31]

When select a file with FilePicker.platform.pickFiles();, the selected file will be copied to the cache directory of the app.
So there is no need to request the manage all files permission if "Select file path" is pressed.

(Ideally, manager should get the file path directly without copying, though.)

[Francesco146]

@kitadai31 I'll remove the check for all permissions in pickFiles, but idk if the second approach is doable rn

edit: not doable, here's why