fix(ffi): avoid infinite loop in HandleClipboardEvents when not on Windows (#846)

When running on non-Windows, HandleClipboardEvents will create an
infinite loop consuming 100% CPU.
Now, we call HandleClipboardEvents only when on Windows.

Author: MihaMarkic

ffi/dotnet/Devolutions.IronRdp.AvaloniaExample/MainWindow.axaml.cs

@@ -112,7 +112,10 @@ private void OnOpened(object? sender, EventArgs e)
             this._activeStage = ActiveStage.New(res);
             this._framed = framed;
             ReadPduAndProcessActiveStage();
-            HandleClipboardEvents();
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                HandleClipboardEvents();
+            }
         });
     }