When the user choose "Open Resources Folder", check if there is a app-private AppData directory, then show a message box to inform the user about the redirected AppData and let the user choose which directory to open. This only applies to the Microsoft Store / MSIX package.
The info is also shown in the resource location settings page:
TODO (maybe): Improve the path checking to be a bit more intelligent so it doesn't only work for I don't think this is necessary.%APPDATA%\krita but also other paths under %APPDATA%? Do we really need this though?
This is also useful for 5.0, but since it adds several strings I'll target 5.1 for now.