LibWeb: Make DOMImplementation GC-allocated

Author: https://github.com/awesomekling
Commit: 967a3e5a45
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

@@ -464,7 +464,6 @@ class DocumentFragmentWrapper;
 class DocumentTypeWrapper;
 class DocumentWrapper;
 class DOMExceptionWrapper;
-class DOMImplementationWrapper;
 class DOMParserWrapper;
 class DOMPointWrapper;
 class DOMPointReadOnlyWrapper;