streams: update tests to use new property for accessing streams API
streams: update tests to use new property for accessing streams API

brucetsao/python-devicecloud,digidotcom/python-devicecloud,ctrlaltdel/python-devicecloud,michaelcho/python-devicecloud,ctrlaltdel/python-devicecloud,brucetsao/python-devicecloud,digidotcom/python-devicecloud,michaelcho/python-devicecloud