Revert "fix 404 for adding"

This reverts commit eacbadb.

Author: SivanYeh

src/proposals/views/mixins.py

@@ -25,6 +25,8 @@ def can_edit(self):
         return reg.get(f'{settings.CONFERENCE_DEFAULT_SLUG}.proposals.editable', False)
 
     def dispatch(self, request, *args, **kwargs):
+        if not self.can_edit():
+            raise Http404
         return super().dispatch(request, *args, **kwargs)