LibWeb: Fix currentColor as a background-color (and maybe other places)

This moves color to be the first value resolved, this ensures that
calls to .to_color() on style values for other properties will always
be able to resolve the current color.

This change fixes the `background-color: currentColor` example in
colors.html.

Userland/Libraries/LibWeb/Layout/Node.cpp

@@ -262,6 +262,9 @@ void NodeWithStyle::apply_style(const CSS::StyleProperties& computed_style)
 {
     auto& computed_values = static_cast<CSS::MutableComputedValues&>(m_computed_values);
 
+    // NOTE: color must be set first to ensure currentColor can be resolved in other properties (e.g. background-color).
+    computed_values.set_color(computed_style.color_or_fallback(CSS::PropertyID::Color, *this, CSS::InitialValues::color()));
+
     // NOTE: We have to be careful that font-related properties get set in the right order.
     //       m_font is used by Length::to_px() when resolving sizes against this layout node.
     //       That's why it has to be set before everything else.
@@ -531,8 +534,6 @@ void NodeWithStyle::apply_style(const CSS::StyleProperties& computed_style)
         const_cast<CSS::AbstractImageStyleValue&>(*m_list_style_image).load_any_resources(document());
     }
 
-    computed_values.set_color(computed_style.color_or_fallback(CSS::PropertyID::Color, *this, CSS::InitialValues::color()));
-
     // FIXME: The default text decoration color value is `currentcolor`, but since we can't resolve that easily,
     //        we just manually grab the value from `color`. This makes it dependent on `color` being
     //        specified first, so it's far from ideal.