Expand GLOB pattern capability on FilePickerFileType

[MajesticBevans]

Is your feature request related to a problem? Please describe.

As far as I understand it, FilePickerFileType currently only recognises the * wildcard character, rather than the other possibilities with GLOB pattern matching.

Describe the solution you'd like

?, [] and ! be added as well

Describe alternatives you've considered

No response

Additional context

No response

[maxkatz6]

Keep in mind this pattern should be supported on all platforms, where we use GLOB patterns.

In most cases we pass pattern "as is" to the platform
Windows: https://github.com/AvaloniaUI/Avalonia/blob/master/src/Windows/Avalonia.Win32/Win32StorageProvider.cs#L250
FreeDesktop: https://github.com/AvaloniaUI/Avalonia/blob/master/src/Avalonia.FreeDesktop/DBusSystemDialog.cs#L201
GTK: https://github.com/AvaloniaUI/Avalonia/blob/master/src/Avalonia.X11/NativeDialogs/GtkNativeFileDialogs.cs#L123

And we only handle them ourselves for managed file picker, which is low priority: https://github.com/AvaloniaUI/Avalonia/blob/master/src/Avalonia.Dialogs/Internal/ManagedFileChooserFilterViewModel.cs#L21-L23

Meaning, this request can only be implemented on managed file picker, and if Windows and Linux already handle extended syntax.