Commit https://github.com/odoo/odoo/commit/137c4f5d76b55c3dd3c4f593de484aadfcf5e6da?w=1#diff-6a334b274d95fb88a4fbc29b910fbb59R2120 introduced a bug as it is using a function which is defined in another asset. This is fine for connected users but not for summernote-only users like public users on the forum. The reason the line was introduced is unsure so it is simply removed for now. The bug it was supposed to fix will be fixed later if it ever needs to be.