Set default warehouse in POS order from session config

[rianmz-genz]

Currently, POS orders do not inherit the warehouse from the session configuration. This can lead to incorrect warehouse assignment when processing orders, especially in multi-warehouse setups.

The default warehouse for POS orders should be set automatically based on session.config_id.picking_type_id.warehouse_id.id. This ensures consistency and avoids manual warehouse selection when confirming POS orders.

Manually setting the warehouse in each POS order (prone to errors).
Using a separate module to extend POS functionality (adds unnecessary complexity).

This change aligns with Odoo’s default behavior in stock operations, where warehouses are inherited from session configurations. Implementing this at the POS level would improve automation and reduce human errors in warehouse selection.