[views] Deactivate relationwidget's creation form

I don't like it and it doesn't work well.

Closes #17066566

cubicweb_seda/views/widgets.py

@@ -24,6 +24,13 @@ from cubicweb.uilib import js
 from cubicweb.web import formfields as ff, formwidgets as fw
 from cubicweb.web.views import ajaxcontroller, autoform, formrenderers
 
+from cubes.relationwidget import views as rwdg
+
+
+# deactivate relation widget's creation form by default, it causes some js error if e.g. there are
+# some calendar widgets. Also, we don't really want that from an UX POV, IMO.
+rwdg.SearchForRelatedEntitiesView.has_creation_form = False
+
 
 def configure_relation_widget(req, div, search_url, title, multiple, validate):
     """Build a javascript link to invoke a relation widget