How to reproduce:
- Create a product tracked by lot;
- Create two receipts for this product;
- Use the same lot name in the two receipts;
- Try to validate the two receipts in the same time
=> `ValidationError` will trigger in the `_check_unique_lot`
constrain of the production lot.
task-2646107
X-original-commit: cf018e9f215336ef19e0a517d4e116f0da26850e
Part-of: odoo/odoo#78189