[FIX] pos_sale: group_by for POS in dashboard
[FIX] pos_sale: group_by for POS in dashboard

Steps to reproduce the bug:

-Go to Sales > Dashboard > Point of Sale > Settings
-Set nothing as group_by value
-Go back to Dashboard

Bug:

A traceback was raised.

opw:1881444

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo