[FIX] sale_stock: display qty_at_date_widget on form view

Before this commit,Widget "qty_at_date_widget" was only displayed on Sales order line form view.

Now we are showing Widget "qty_at_date_widget" on Sales order line form view as well.  (https://prnt.sc/v5inaw

)

closes odoo/odoo#60664

Signed-off-by: Arnold Moyaux <amoyaux@users.noreply.github.com>