There was an issue when saving the LinkDialog with invalid data. The _DialogLinkWidget.save methods return values were not consistent. Also, tests are added for the regular menus edition. The existing mega menu edition test was not played from the python test suite. task-2513588 X-original-commit: 725cad3478e5ab12ad7f0cf5166a2b968a1373da Part-of: odoo/odoo#81351 Co-authored-by: Arthur Detroux (ard) <ard@odoo.com>