Fix expectations in order_shipment_spec
Fix expectations in order_shipment_spec

Some depreacted calls to #find_by_* had previously been updated elsewhere, but the spec was still checking if the object received the #find_by_shipping_method_id message.

Fixes:

  85) OrderShipment#select_shipping_method when order has a shipment when shipping_method_id is not valid for the order returns nil
      Failure/Error: expect(shipment.shipping_rates).to receive(:find_by_shipping_method_id).with(invalid_shipping_method_id) { nil }

        (#<ActiveRecord::Associations::CollectionProxy []>).find_by_shipping_method_id(1312)
            expected: 1 time with arguments: (1312)
            received: 0 times
      # ./spec/models/concerns/order_shipment_spec.rb:53:in `block (5 levels) in <top (required)>'

openfoodfoundation/openfoodnetwork,Matt-Yorkley/openfoodnetwork,openfoodfoundation/openfoodnetwork,Matt-Yorkley/openfoodnetwork,lin-d-hop/openfoodnetwork,openfoodfoundation/openfoodnetwork,Matt-Yorkley/openfoodnetwork,lin-d-hop/openfoodnetwork,mkllnk/openfoodnetwork,mkllnk/openfoodnetwork,Matt-Yorkley/openfoodnetwork,openfoodfoundation/openfoodnetwork,mkllnk/openfoodnetwork,lin-d-hop/openfoodnetwork,lin-d-hop/openfoodnetwork,mkllnk/openfoodnetwork