Preview: Clicking folder open button does nothing

Versions

• OS: MacOS
• Gajim: 2.4.4

Steps to reproduce the problem

1. Get file send where no preview is available
2. Click the folder open button
3. Nothing happens

Context

This is because FileLauncher.open_containg_folder() does nothing on MacOS see https://gitlab.gnome.org/GNOME/gtk/-/issues/8070

We could do this ourself by calling

https://developer.apple.com/documentation/appkit/nsworkspace/activatefileviewerselecting(_:)