When checking if the picking is auto-batchable, calling
`_is_auto_batchable()` with `picking` having it's default value `None`,
it would raise an error as it would try to access the `weight` property
from a NoneType.
Part of task-2985735
X-original-commit: 574ff569e5b9a043d29b7113f8bfe3a549a74d72
Part-of: odoo/odoo#102382
Improves the auto-batcher, allowing it to also group by :
- Carrier
While adding a new restriction on the batch size as well :
- Max weight per batch
Task-2670580
Part-of: odoo/odoo#81533