Part of https://github.com/odoo/odoo/commit/f4ba72a7593b67595852fc52ec0997d3276dbc67 became useless after forward-port in the new editor. Indeed, that commit handled what happened with data-editor-message attributes on save but as the new editor can discard changes without reloading the page, the forward-port of that commit made the code handle the attribute removal on editor *close*. closes odoo/odoo#31143