Can not delete purchase requests has purchase line and draft state and origin from stock.order_point

When a user run "Stock supply" wizard, try to delete purchase requests in draft state and origin is "stock.order_point".

Since #11479 (closed) remove ('purchase_line', '=', None). Current code, return purchase request in draft state and maybe has related to purchase line.

Finally, purchase_request module can not delete a purchase request in draft state and has "purchase line":

You cannot delete purchase request "%(request)s" because it is purchased.