Merge pull request #3954 from GordonSmith/HPCC-8786

HPCC-8786 Graph "Advanced/Show SVG" broken

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>

esp/files/scripts/GraphWidget.js

@@ -158,7 +158,7 @@ require([
             },
 
             getSVG: function () {
-                return this.plugin.getSVG();
+                return this._plugin.getSVG();
             },
 
             getXGMML: function () {