[FIX] web_kanban: t-att(f)-class for kanban buttons
[FIX] web_kanban: t-att(f)-class for kanban buttons

The pre-processing of kanban qweb templates dropped the t-att(f)-class
of button and tags with a valid type attr (object, action, ...).

ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,dfang/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,hip-odoo/odoo,ygol/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,dfang/odoo,ygol/odoo,ygol/odoo,ygol/odoo,hip-odoo/odoo