LibHTML: Respect the CSS "color" property for text

Also remove the color values from the ComputedStyle object and get them
via StyleProperties instead.

At the moment, we only handle colors that Color::from_string() parses.

Libraries/LibHTML/Layout/LayoutText.cpp

@@ -227,6 +227,8 @@ void LayoutText::render(RenderingContext& context)
     auto& painter = context.painter();
     painter.set_font(*m_font);
 
+    auto color = style_properties().color_or_fallback("color", Color::Black);
+
     for (auto& run : m_runs) {
         Rect rect {
             run.pos.x(),
@@ -234,6 +236,6 @@ void LayoutText::render(RenderingContext& context)
             m_font->width(run.text),
             m_font->glyph_height()
         };
-        painter.draw_text(rect, run.text);
+        painter.draw_text(rect, run.text, TextAlignment::TopLeft, color);
     }
 }