dashboards: correct avg qps graph desc

The avg QPS graph on the replication graph previously described the
metric as "Exponentially weighted average", however this is not true.

This commit updates the description to just be "moving average" which is
accurate. Note that follow the workload does use an exponentially
weighted value, however the metric in the dashboard is not the same.

This commit also updates the graph header to include Replica in the
title: "Average Replica Queries per Node". QPS is specific to
replicas. This is already mentioned in the description.

Release note (ui change): The description of the average QPS graph in the
replication metrics dashboard no longer claims the average is
exponentially weighted.

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

@@ -87,8 +87,10 @@ export default function (props: GraphDashboardProps) {
     </LineGraph>,
 
     <LineGraph
-      title="Average Queries per Node"
-      tooltip={`Exponentially weighted moving average of the number of KV batch requests processed by leaseholder replicas on each node per second. Tracks roughly the last 30 minutes of requests. Used for load-based rebalancing decisions.`}
+      title="Average Replica Queries per Node"
+      tooltip={`Moving average of the number of KV batch requests processed by
+         leaseholder replicas on each node per second. Tracks roughly the last
+         30 minutes of requests. Used for load-based rebalancing decisions.`}
     >
       <Axis label="queries">
         {_.map(nodeIDs, nid => (