LibWeb: Store stop-opacity in computed form in ComputedProperties

Author: https://github.com/Calme1709
Commit: c045969234
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/6112
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/tcl3 ✅

Libraries/LibWeb/CSS/CSSStyleProperties.cpp

@@ -813,10 +813,6 @@ RefPtr<StyleValue const> CSSStyleProperties::style_value_for_computed_property(L
 
         return get_computed_value(property_id);
     }
-    case PropertyID::StopOpacity: {
-        auto opacity = layout_node.computed_values().stop_opacity();
-        return NumberStyleValue::create(opacity);
-    }
     case PropertyID::StrokeOpacity: {
         auto opacity = layout_node.computed_values().stroke_opacity();
         return NumberStyleValue::create(opacity);