Impacted versions: 9.0

Steps to reproduce:

* Create an MTO product with 
  * Product Type: Stockable Product
  * Routes: "Buy" and "Make to Order"
* Update Qty on Hand to any quantity (i.e, 2).
* Create a sales order with this product and a number <= to the one in the step before.
* Confirm the sales order.

Current behavior:

The created delivery picking appears in state "Reserved" and the current quantity on stock has been reserved, allowing you to transfer that stock.

Expected behavior:

The created delivery picking should be in "Waiting another operation", or at least in "Waiting availability" until the purchase order is confirmed (if you have defined a supplier for the product and the procurement creates the purchase order), which seems to be the current behavior when there's no stock available (is this also correct, as it allows to manually reserve?).
"""
            Will check if the resupply routes to this warehouse follow the changes of number of receipt steps
        """
        
        route_obj = self.pool.get("stock.location.route")
        pull_obj = self.pool.get("procurement.rule")
        routes = route_obj.search(cr, uid, [('supplied_wh_id','=', warehouse.id)], context=context)
        pulls= pull_obj.search(cr, uid, ['&', ('route_id', 'in', routes), ('location_src_id.usage', '=', 'transit')])
        if pulls:
            pull_obj.write(cr, uid, pulls, {'location_id': new_location}, context=context)
    def _check_resupply(self, cr, uid, warehouse, reception_new, delivery_new, context=None):
        if reception_new:
            old_val = warehouse.reception_steps
            new_val = reception_new
            change_to_one = (old_val != 'one_step' and new_val == 'one_step')
            change_to_multiple = (old_val == 'one_step' and new_val != 'one_step')
            if change_to_one or change_to_multiple:
                new_location = change_to_one and warehouse.lot_stock_id.id or warehouse.wh_input_stock_loc_id.id
                self._check_reception_resupply(cr, uid, warehouse, new_location, context=context)
        if delivery_new:
            old_val = warehouse.delivery_steps
            new_val = delivery_new
            change_to_one = (old_val != 'ship_only' and new_val == 'ship_only')
            change_to_multiple = (old_val == 'ship_only' and new_val != 'ship_only')
            if change_to_one or change_to_multiple:
                new_location = change_to_one and warehouse.lot_stock_id.id or warehouse.wh_output_stock_loc_id.id 
                self._check_delivery_resupply(cr, uid, warehouse, new_location, change_to_multiple, context=context)
    def write(self, cr, uid, ids, vals, context=None):