pubsub: unflake TestIntegration_PublicTopic
pubsub: unflake TestIntegration_PublicTopic

As documented, StreamingPull will sometimes return an error upon
stream disconnects and this is not indicative of the test failing.
This fix removes the receive block, since the ability to
create a subscription is sufficient for testing that the
pubsub.TopicInProject method works.

See https://cloud.google.com/pubsub/docs/pull#streamingpull_has_a_100_error_rate_this_is_to_be_expected

Fixes #1967

Change-Id: Ie86841ea4fcc3eef931742f1a92aa62f272ebd2e
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/55951
Reviewed-by: Cody Oss <f11fa1e55ff5638510f5bf86ea76672a630250f9@google.com>
Reviewed-by: Chris Cotter <b879ae7d4b52f11ce9f60d9854075eb8eebaf7a9@google.com>

googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go