ui: Plot circuit breaker tripped events as a rate values

Before, Circuit Breaker Tripped events chart displayed accumulated number
of events since process started.

Now, it displays number of events per aggregated interval of time.

Release note (ui change): Circuit Breaker Tripped events chart displays
rate of events per interval instead of accumulated number of events.

pkg/kv/kvserver/metrics.go

@@ -1404,7 +1404,7 @@ Replicas in this state will fail-fast all inbound requests.
 	// Replica circuit breaker.
 	metaReplicaCircuitBreakerCumTripped = metric.Metadata{
 		Name:        "kv.replica_circuit_breaker.num_tripped_events",
-		Help:        `Number of times the per-Replica circuit breakers tripped since process start.`,
+		Help:        `The number of circuit breaker events occurred per second across all nodes since the process started.`,
 		Measurement: "Events",
 		Unit:        metric.Unit_COUNT,
 	}

pkg/ui/workspaces/db-console/src/views/cluster/containers/nodeGraphs/dashboards/graphTooltips.tsx

@@ -161,7 +161,7 @@ export const CircuitBreakerTrippedReplicasTooltip: React.FC = () => (
 
 export const CircuitBreakerTrippedEventsTooltip: React.FC = () => (
   <div>
-    Number of times the per-Replica circuit breakers tripped since process
-    start.
+    The number of circuit breaker events occurred per second across all
+    nodes since the process started.
   </div>
 );

pkg/ui/workspaces/db-console/src/views/cluster/containers/nodeGraphs/dashboards/replication.tsx

@@ -218,7 +218,7 @@ export default function(props: GraphDashboardProps) {
             name="cr.store.kv.replica_circuit_breaker.num_tripped_events"
             title={nodeDisplayName(nodesSummary, nid)}
             sources={storeIDsForNode(nodesSummary, nid)}
-            downsampler={TimeSeriesQueryAggregator.MAX}
+            nonNegativeRate
           />
         ))}
       </Axis>