[FIX] purchase_requistion: call for tender zero lines

Usecase to reproduce:
- Create a purchase requistion with type Call For Tender
- Update a line and set the price to zero.

UserError 'You cannot confirm the blanket order without price.' raised.
It happens because the write don't process the same check than create
and don't check if the purchase_requistion is a blanket order or a call
for tender. It also doens't check the current state of the
purchase_requisition.

closes odoo/odoo#39883

Task: 2120211
Signed-off-by: Arnold Moyaux <amoyaux@users.noreply.github.com>

addons/purchase_requisition/models/purchase_requisition.py

@@ -224,7 +224,9 @@ class PurchaseRequisitionLine(models.Model):
     def write(self, vals):
         res = super(PurchaseRequisitionLine, self).write(vals)
         if 'price_unit' in vals:
-            if vals['price_unit'] <= 0.0:
+            if vals['price_unit'] <= 0.0 and any(
+                    requisition.state not in ['draft', 'cancel', 'done'] and
+                    requisition.is_quantity_copy == 'none' for requisition in self.mapped('requisition_id')):
                 raise UserError(_('You cannot confirm the blanket order without price.'))
             # If the price is updated, we have to update the related SupplierInfo
             self.supplier_info_ids.write({'price': vals['price_unit']})