Prior to this commit, there was an unwanted margin before the "Go to Website" button in `button_box` located in the modal window of the course parameters. This commit removes this margin to maintain consistency with the `button_box` layout. task-3580610 closes odoo/odoo#141671 X-original-commit: 5530c846bf4c4b79c5e79e943c6859843a53187b Signed-off-by: Pierre Paridans (app) <app@odoo.com>