LibWeb: Don't draw zero-length line for text-decoration: blink

This patch doesn't make any visible change but increases the
correctness of the text-decoration: blink path. Previously the painter
would be instructed to draw a line that doesn't have any length when
encountering the blink property instead of simply doing nothing.

Userland/Libraries/LibWeb/Layout/TextNode.cpp

@@ -65,6 +65,7 @@ void TextNode::paint_text_decoration(Gfx::Painter& painter, LineBoxFragment cons
     } break;
     case CSS::TextDecorationLine::Blink:
         // Conforming user agents may simply not blink the text
+        return;
         break;
     }