Merge pull request #6245 from AvaloniaUI/fixes/osx-getting-stuck-in-fullscreen

OSX - window state - keep field in sync.

native/Avalonia.Native/src/OSX/window.mm

@@ -740,6 +740,7 @@ private:
                 }
                 
                 _lastWindowState = state;
+                _actualWindowState = state;
                 WindowEvents->WindowStateChanged(state);
             }
         }