Port: add client ID to TWEs in activity log [vault-3136] (#12820)

* port for tracking twes as clients

* comment clean up

* changelog

* change changelog entry phrasing

command/operator_usage.go

@@ -191,8 +191,11 @@ type UsageCommandNamespace struct {
 type UsageResponse struct {
 	namespacePath string
 	entityCount   int64
-	tokenCount    int64
-	clientCount   int64
+	// As per 1.9, the tokenCount field will contain the distinct non-entity
+	// token clients instead of each individual token.
+	tokenCount int64
+
+	clientCount int64
 }
 
 func jsonNumberOK(m map[string]interface{}, key string) (int64, bool) {