graph_editor: update to support recent renderjs

RSVP.Monitor no longer exist.

Use the gadget's own monitor instead (not sure it is safe)

bt5/erp5_graph_editor/SkinTemplateItem/portal_skins/erp5_graph_editor/dream_graph_editor/jsplumb/jsplumb.js.js

@@ -827,12 +827,11 @@
      });
      draggable(gadget);
 
-     this.props.nodes_click_monitor = RSVP.Monitor();
+     this.props.nodes_click_monitor = this.__monitor;
      return RSVP.all([waitForDrop(gadget),
        waitForConnection(gadget),
        waitForConnectionDetached(gadget),
-       waitForConnectionClick(gadget),
-       gadget.props.nodes_click_monitor
+       waitForConnectionClick(gadget)
      ]);
    });