Refactor Win32 file dialog API

[AmelBawa-msft]

Summary of the pull request

• Added support for file dialogs using win32 API:

  • Open file dialog

  using var fileDialog = new WindowOpenFileDialog();
  
  fileDialog.AddFileType("YAML files", ".yaml", ".yml", ".winget");
  fileDialog.AddFileType("Image files", ".png", ".gif");
  
  StorageFile? file = await fileDialog.ShowAsync(window);

  • Open folder dialog

  using var folderDialog = new WindowOpenFolderDialog();
  
  StorageFolder? folder = await folderDialog.ShowAsync(window);

  • Save file dialog

  using var fileDialog = new WindowSaveFileDialog();
  
  fileDialog.AddFileType("YAML files", ".yaml", ".yml", ".winget");
  fileDialog.AddFileType("Image files", ".png", ".gif");
  
  var filePath = fileDialog.Show(window);

• This PR also replaces the folder picker usage in Repo and Dev Drive pages preventing the app from crashing in admin mode

References and relevant issues

Detailed description of the pull request / Additional comments

Validation steps performed

PR checklist

• Closes #xxx
• Tests added/passed
• Documentation updated

[krschau]

❤️ docs

[krschau]

@joadoumie Let's use this -- doesn't matter in widgets which can't run as admin, but potentially someone could use the AC picker somewhere else.

[joadoumie]

@joadoumie Let's use this -- doesn't matter in widgets which can't run as admin, but potentially someone could use the AC picker somewhere else.

This is just to replace the file picker for #2477?

[krschau]

@joadoumie Let's use this -- doesn't matter in widgets which can't run as admin, but potentially someone could use the AC picker somewhere else.

This is just to replace the file picker for #2477?

I haven't really looked into it yet, but if it makes sense we should use this new, admin-safe API when we launch the file picker from AC.