[13.0][FIX] stock_account: average unit cost price

When the cost of a product is set to a value below the currency rounding
the average purchase cost price will be wrongly set to zero.

It can happen for product sold in large quantity, that the cost of one product
must be smaller than the smallest unit of currency.

Instead of doing the zero check with currency precision using the
product price precision, which is the one used for the `standard_price`
fields, makes more sense and fixes the problem.

opw-2601121

closes odoo/odoo#73985

X-original-commit: 251be6b943ea8c3f274bb0863d0af3f7c6b8d10d
Signed-off-by: Arnold Moyaux <amoyaux@users.noreply.github.com>

addons/stock_account/models/stock_move.py

@@ -32,10 +32,11 @@ class StockMove(models.Model):
         """ Returns the unit price to value this stock move """
         self.ensure_one()
         price_unit = self.price_unit
+        precision = self.env['decimal.precision'].precision_get('Product Price')
         # If the move is a return, use the original move's price unit.
         if self.origin_returned_move_id and self.origin_returned_move_id.sudo().stock_valuation_layer_ids:
             price_unit = self.origin_returned_move_id.sudo().stock_valuation_layer_ids[-1].unit_cost
-        return not self.company_id.currency_id.is_zero(price_unit) and price_unit or self.product_id.standard_price
+        return not float_is_zero(price_unit, precision) and price_unit or self.product_id.standard_price
 
     @api.model
     def _get_valued_types(self):