gadget: let render.js generate a scope automatically

This fixes the case of gadget fields in listboxes.

product/ERP5Form/GadgetField.py

@@ -31,7 +31,6 @@ class GadgetWidget(Widget.TextWidget):
   def render_view(self, field, value, REQUEST=None, render_prefix=None, key=None):
     kw = {
       'data-gadget-sandbox': field.get_value('js_sandbox'),
-      'data-gadget-scope': field.id,
       'data-gadget-url': field.get_value('gadget_url'),
       'data-gadget-value': value,
     }