LibWeb: Make CSSRuleList GC-allocated

Author: https://github.com/awesomekling
Commit: 5d6cb9cbdb
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 CSSFontFaceRuleWrapper;
 class CSSGroupingRuleWrapper;
 class CSSImportRuleWrapper;
 class CSSMediaRuleWrapper;
-class CSSRuleListWrapper;
 class CSSRuleWrapper;
 class CSSStyleDeclarationWrapper;
 class CSSStyleRuleWrapper;