[FIX] stock: label printed twice

Steps to reproduce:
- enable PICK + PACK + SHIP
- in Inventory/Configuration/Operations Types
- check print label in PACK

Bug:
print label is already enabled by default in the SHIP Operation
and it's not possible for the user to edit it.

Fix:
allow the user to disable print label on the SHIP Operation

opw-3085428

closes odoo/odoo#115038

Signed-off-by: William Henrotin (whe) <whe@odoo.com>