LibWeb: Add support for inline SVG element scripts

Author: https://github.com/shannonbooth
Commit: 4821d284c6
Pull-request: https://github.com/SerenityOS/serenity/pull/21227
Reviewed-by: https://github.com/AtkinsSJ ✅
Reviewed-by: https://github.com/kemzeb

Userland/Libraries/LibWeb/Forward.h

@@ -618,6 +618,7 @@ class SVGPathElement;
 class SVGPolygonElement;
 class SVGPolylineElement;
 class SVGRectElement;
+class SVGScriptElement;
 class SVGSVGElement;
 class SVGTitleElement;
 }