Switch to native dialog for ManagedFileChooser

[AuroraZiling]

Considering that the ManagedFileChooser is still a work in progress, and with SukiUI nearing its release, along with the fact that different operating systems have their own unique features for file dialogs (like Quick Access in Windows), I believe it's no longer necessary to customize ManagedFileChooser. Using the native system dialog would be a better approach.