We should be able to reference other upgrade/downgrade tests here, e.g.

https://github.com/10gen/mongo/blob/2ecd33d2714b999e600743e754921c90d56d298a/jstests/multiVersion/genericBinVersion/query-integration-observability/memory_tracking_upgrade_downgrade.js#L55 

We should assert that when we run queryStats with sampling on and the cluster is on 8.3, we see CBR metrics. And when the cluster is mixed 8.2/8.3 or fully downgraded, we should not see CBR metrics.