Implement YaComponentPluginImpl destructor

When the object gets dropped through the reference counting system, the
object should also be dropped in the Wine plugin host.

src/common/serialization/vst3.h

@@ -68,7 +68,8 @@ struct WantsPluginFactory {
  * encodes the information we request or the operation we want to perform. A
  * request of type `ControlRequest(T)` should send back a `T::Response`.
  */
-using ControlRequest = std::variant<YaComponent::Create, WantsPluginFactory>;
+using ControlRequest =
+    std::variant<YaComponent::Create, YaComponent::Destroy, WantsPluginFactory>;
 
 template <typename S>
 void serialize(S& s, ControlRequest& payload) {