Samples checks are failing

[parthea]

Samples checks recently started failing. See https://github.com/googleapis/python-analytics-admin/commits/master. Based on #170, it appears that the samples need to be updated to support dataStreams.

From the test log, when using AndroidAppDataStream, we see error

        except grpc.RpcError as exc:
>           raise exceptions.from_grpc_error(exc) from exc
E           google.api_core.exceptions.InvalidArgument: 400 The value for the 'parent' field was invalid but must be in format 'properties/123/dataStreams/456'.

.nox/py-3-7/lib/python3.7/site-packages/google/api_core/grpc_helpers.py:68: InvalidArgument

[parthea]

Hi @ikuleshov,

Please could you take a look?

[parthea]

I'm going to try tackling this in #195