Before this commit, when browsing a filterMenu with the keyboard, the CustomFilterMenu was not focusable. This is because its root node changed from `button` to `span` which is not focusable by default. After this commit, the CustomFilterMenu is focusable and the root node has been replaced back by a button closes odoo/odoo#72738 Signed-off-by: Géry Debongnie (ged) <ged@openerp.com>