[FIX] pos_cash_rounding : Unpaid orders when using cash rounding

Current behavior :
When using cash rouding method "HALF-UP" if the difference between the rounded price and the original price was exactly the half of the cash rounding, the order would appear as unpaid.

Steps to reproduce :
- Create a rounding method of 0.5 (half-up)
- Sell a product for 11.25
- The order appears unpaid in the PoS orders list view

opw-2593687

closes odoo/odoo#81830

X-original-commit: 3c452f9f731490ce94331f40ffdbe1957052000e
Signed-off-by: Grazioso Andrea (agr) <agr@odoo.com>
Signed-off-by: Engels Robin (roen) <roen@odoo.com>

addons/point_of_sale/models/pos_order.py

@@ -569,7 +569,7 @@ class PosOrder(models.Model):
                 maxDiff = currency.round(self.config_id.rounding_method.rounding)
 
             diff = currency.round(self.amount_total - self.amount_paid)
-            if not abs(diff) < maxDiff:
+            if not abs(diff) <= maxDiff:
                 raise UserError(_("Order %s is not fully paid.", self.name))
 
         self.write({'state': 'paid'})