Since https://github.com/odoo/odoo/commit/2ad49ec93e39ae5d59ccc17884408870e1c86c5e

,
all dialogs were able to be closed by clicking on the backdrop which was
not a desired behavior.

Indeed, the 'backdrop' option of the BS component was misused.

closes odoo/odoo#35300

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>