LibWeb: Change SVGContext initial fill_color to transparent

This patch changes the initialization of the fill_color of an SVGContext
to transparent instead of black to not draw a black filling if the
elements fill_color is defined as "none".

Userland/Libraries/LibWeb/SVG/SVGContext.h

@@ -35,7 +35,7 @@ public:
 
 private:
     struct State {
-        Gfx::Color fill_color { Gfx::Color::Black };
+        Gfx::Color fill_color { Gfx::Color::Transparent };
         Gfx::Color stroke_color { Gfx::Color::Transparent };
         float stroke_width { 1.0 };
     };