fix(Avalonia): move screenshotting to initialization step

This should fix region screenshots on macOS being cut off from the transition from the regular multi tasking desktop to a seperate desktop for a fullscreened application

Author: BrycensRanch

SnapX.Avalonia/Views/RegionSelectorWindow.axaml

@@ -4,10 +4,10 @@
     Closed="OnClosed"
     Cursor="Hand"
     Focusable="True"
+    Initialized="OnInit"
     KeyDown="OnKeyDown"
     KeyUp="OnKeyDown"
     LostFocus="OnLostFocus"
-    Opened="OnOpened"
     PointerMoved="OnPointerMoved"
     PointerPressed="OnPointerPressed"
     PointerReleased="OnPointerReleased"

SnapX.Avalonia/Views/RegionSelectorWindow.axaml.cs

@@ -218,7 +218,7 @@ private void OnKeyDown(object? sender, KeyEventArgs e)
     }
     private readonly Dictionary<Window, WindowBase?> _ownershipMap = new();
 
-    private async void OnOpened(object? Sender, EventArgs EventArgs)
+    private async void OnInit(object? Sender, EventArgs EventArgs)
     {
         foreach (var win in App.MyMainWindow?.OwnedWindows.Where(w => w != this && w.IsVisible) ?? [])
         {