[FIX] stock: scheduled date required
[FIX] stock: scheduled date required

The field `scheduled_date` on `stock.picking` is used to set the field
`date_expected` on `stock.move`. Since `date_expected` is required, we
should make `scheduled_date` required as well.

Closes #22684

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