[IMP] sale: display expiry date on quotation portal view

Currently on the portal, when a quotation has a limited validity
period, it is expried as "This offers exprires in" Xdays but X is computed
always with a additional day and its show "expries in 0 days" so
after this commit it shows the expiry date
(like This offers expires on 20 december 2020) on portal view
instead of X duration.

closes odoo/odoo#46649

Task: 2186428
Closes: #46649
Related: odoo/upgrade#874
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>