add pie trace to legend valign mock

Author: etpinard

test/image/baselines/legend_valign_top.png

@@ -10,15 +10,22 @@
       "name": "Also super long name<br>Also super long name<br>Also super long name",
       "type": "scatter",
       "showlegend": true
+    },
+    {
+        "type": "pie",
+        "labels": ["a very<br>long<br>legend item", "a", "b", "c"],
+        "values": [10, 15, 13, 17],
+        "domain": {"x": [0.5, 1]}
     }
   ],
   "layout": {
     "width": 800,
+    "xaxis": {"domain": [0, 0.5]},
     "legend": {
       "bgcolor": "rgba(0,255,255,1)",
       "valign": "top",
       "font": {
-        "size": 20
+        "size": 10
       }
     }
   }