Legend: set tspan.line's x before expandMargin

* Ensure the position of the `tspan.line`s is set before computing the
  legend dimensions and expanding the margins.

* The baseline image for `pseudo_html.json` needed updating because it
  has a multi-line legend.

Author: n-riesco

src/components/legend/draw.js

@@ -334,11 +334,12 @@ function drawTexts(gd, context, legendItem, traces) {
 
     function textLayout(s) {
         Plotly.util.convertToTspans(s, function() {
+            s.selectAll('tspan.line').attr({x: s.attr('x')});
+
             if(gd.firstRender) {
                 computeLegendDimensions(gd, traces);
                 expandMargin(gd);
             }
-            s.selectAll('tspan.line').attr({x: s.attr('x')});
         });
     }