Review docs recommending no thresholds and no summaries only for cloud when running large tests

[immavalls]

The doc https://k6.io/docs/testing-guides/running-large-tests/#when-streaming-use-no-thresholds-and-no-summary recommends using --no-thresholds and --no-summary when the output is cloud. We've found that when streaming long-running tests to prometheus, influxdb, etc. we can also recommend that, so we should review the writing.

E.g. https://community.grafana.com/t/statsd-how-to-periodically-emit-and-flush-k6-data-to-cloudwatch/99968/7