fix: addDestroySwapchain argument to createViewer() (true by default). This is only used on iOS/macOS where a single swapchain is shared between all render targets

thermion_flutter/thermion_flutter_platform_interface/lib/thermion_flutter_platform_interface.dart

@@ -65,7 +65,7 @@ abstract class ThermionFlutterPlatform extends PlatformInterface {
   ///
   ///
   ///
-  Future<ThermionViewer> createViewer() {
+  Future<ThermionViewer> createViewer({bool destroySwapchain = true}) {
     throw UnimplementedError();
   }