[FIX] mrp: done workorder on multiple reserved move lines

Producing a manufacturing order on components with more than one unit
could leads to multiple move line reserved on this component. Marking the
workorder as done, in that case, will trigger an error saying "Cannot set
the done quantity from this stock move, work directly with the move
lines". Instead of setting the quantity done directly, this commit
uses the magical function _set_quantity_done() that manage the case
of more than one move lines.

OPW-1888780

closes odoo/odoo#27773

addons/mrp/models/mrp_workorder.py

@@ -317,8 +317,10 @@ class MrpWorkorder(models.Model):
                 if self.product_id.tracking != 'none':
                     qty_to_add = float_round(self.qty_producing * move.unit_factor, precision_rounding=rounding)
                     move._generate_consumed_move_line(qty_to_add, self.final_lot_id)
-                else:
+                elif len(move._get_move_lines()) < 2:
                     move.quantity_done += float_round(self.qty_producing * move.unit_factor, precision_rounding=rounding)
+                else:
+                    move._set_quantity_done(move.quantity_done + float_round(self.qty_producing * move.unit_factor, precision_rounding=rounding))
 
         # Transfer quantities from temporary to final move lots or make them final
         for move_line in self.active_move_line_ids: