LibWeb: Make MessageChannel GC-allocated

Author: https://github.com/awesomekling
Commit: 2ff7e37048
Pull-request: https://github.com/SerenityOS/serenity/pull/14816
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWeb/Forward.h

@@ -467,7 +467,6 @@ class IdleDeadlineWrapper;
 class ImageDataWrapper;
 class IntersectionObserverWrapper;
 class LocationObject;
-class MessageChannelWrapper;
 class OptionConstructor;
 class Path2DWrapper;
 class RangePrototype;