Remove duplicate method call - datagrid#addFilter doesn't return anything, so have removed the return'd call, and left the other.

Builder/DatagridBuilder.php

@@ -118,7 +118,6 @@ class DatagridBuilder implements DatagridBuilderInterface
 
         $datagrid->addFilter($filter);
 
-        return $datagrid->addFilter($filter);
     }
 
     /**