[IMP] point_of_sale: Add the uom to the order line

If we were using Units of Measure before, the pos order line didn't show what unit we were using. Now we display the Units of Measure in the order line if the option is active.
TASK-ID: 2001995

closes odoo/odoo#33915

Signed-off-by: pimodoo <pimodoo@users.noreply.github.com>

addons/point_of_sale/models/pos_order.py

@@ -1032,6 +1032,7 @@ class PosOrderLine(models.Model):
     tax_ids = fields.Many2many('account.tax', string='Taxes', readonly=True)
     tax_ids_after_fiscal_position = fields.Many2many('account.tax', compute='_get_tax_ids_after_fiscal_position', string='Taxes to Apply')
     pack_lot_ids = fields.One2many('pos.pack.operation.lot', 'pos_order_line_id', string='Lot/serial Number')
+    product_uom_id = fields.Many2one('uom.uom', string='Product UoM', related='product_id.uom_id')
 
     @api.model
     def _prepare_refund_data(self, refund_order_id):

addons/point_of_sale/views/pos_order_view.xml

@@ -38,6 +38,7 @@
                             <tree string="Order lines" editable="bottom">
                                 <field name="product_id"/>
                                 <field name="qty"/>
+                                <field name="product_uom_id" string="UoM" groups="uom.group_uom"/>
                                 <field name="price_unit" widget="monetary"/>
                                 <field name="discount" string="Disc.%" widget="monetary"/>
                                 <field name="tax_ids_after_fiscal_position" widget="many2many_tags" string="Taxes"/>