isSubjectToAdmissionControl is defined largely for CRUD operations, some DDL operations, and operations meant to target the oplog. At present, no cluster commands have definitions for this method. We're now going to be using this condition to decide whether operations should queue at the IngressRequestRateLimiter when queuing is enabled. This ticket tracks evaluating shard commands to see if the old list needs updating, as well as the list of router/cluster commands to see if any of them should not be subjected to admission control.