dbconsole: add tooltop to replication dash ranges chart

The Ranges chart in the replication dashboard can be easily
misinterpreted when in a single node view, because the per-node metric
is only reported by one node for each range. Most commonly, this is the
leaseholder, and if not, the first replica in the range descriptor.

Add a tooltip which explains this nuance, taken from the
documentation.

Epic: None
Resolves: #111055

Release note (ui change): Added a tooltip to the ranges chart on the
replication dashboard, describing the metric in single vs cluster
view.

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

@@ -42,6 +42,9 @@ export default function (props: GraphDashboardProps) {
       title="Ranges"
       sources={storeSources}
       tenantSource={tenantSource}
+      tooltip={`Various details about the status of ranges. In the node view,
+        shows details about ranges the node is responsible for. In the cluster
+        view, shows details about ranges all across the cluster.`}
     >
       <Axis label="ranges">
         <Metric name="cr.store.ranges" title="Ranges" />