[Metrics UI] Use bucketSize from request options for overview query (#…

…145032)

## Summary

This PR fixes #145030 by using the `options.bucketSize` in the
`date_histogram` for the Overview query.

x-pack/plugins/infra/server/routes/overview/lib/create_top_nodes_query.ts

@@ -142,7 +142,7 @@ export const createTopNodesQuery = (
           timeseries: {
             date_histogram: {
               field: '@timestamp',
-              fixed_interval: '1m',
+              fixed_interval: options.bucketSize,
               extended_bounds: {
                 min: options.timerange.from,
                 max: options.timerange.to,

x-pack/test/api_integration/apis/metrics_ui/metrics_overview_top.ts

@@ -47,6 +47,7 @@ export default function ({ getService }: FtrProviderContext) {
 
       expect(series.length).to.be(1);
       expect(series[0].id).to.be('demo-stack-mysql-01');
+      expect(series[0].timeseries[1].timestamp - series[0].timeseries[0].timestamp).to.be(300_000);
     });
   });
 }