[FIX] sale_order_dates: infinite recurssion in effective_date computation
[FIX] sale_order_dates: infinite recurssion in effective_date computation

This is due to the below revision
c1cfbf6436323923517c3b633931d65016970eea

Which used the `write` method on the `order` instead of assigning
the value in the variable `order.effective_date` to set the value,
as it should be done in the new API

opw-693800

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