LibWeb: Stop 'no-repeat' from expanding the background area

Previously, a `background-repeat` value of `no-repeat` in a direction
would cause the image to be drawn at exactly that size. This was fine if
the image was smaller than the element, but if it was larger, it would
draw outside its bounds. Now, it behaves itself. :^)

Userland/Libraries/LibWeb/Painting/BackgroundPainting.cpp

@@ -27,7 +27,7 @@ void paint_background(PaintContext& context, Gfx::IntRect const& background_rect
             // The background rect is already sized to align with 'repeat'.
             break;
         case CSS::Repeat::NoRepeat:
-            image_rect.set_width(background_data.image->width());
+            image_rect.set_width(min(image_rect.width(), background_data.image->width()));
             break;
         }
 
@@ -39,7 +39,7 @@ void paint_background(PaintContext& context, Gfx::IntRect const& background_rect
             // The background rect is already sized to align with 'repeat'.
             break;
         case CSS::Repeat::NoRepeat:
-            image_rect.set_height(background_data.image->height());
+            image_rect.set_height(min(image_rect.height(), background_data.image->height()));
             break;
         }