[DataUsage][Serverless] Add missing tests (elastic#198007)

## Summary

Adds missing UX/API tests for changes added in 
- elastic#193966
- elastic#197056
- elastic#195556
- elastic#196559


### Checklist
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed

---------

Co-authored-by: kibanamachine <[email protected]>

x-pack/plugins/data_usage/common/test_utils/test_query_client_options.ts

@@ -0,0 +1,20 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+/* eslint-disable no-console */
+export const dataUsageTestQueryClientOptions = {
+  defaultOptions: {
+    queries: {
+      retry: false,
+      cacheTime: 0,
+    },
+  },
+  logger: {
+    log: console.log,
+    warn: console.warn,
+    error: () => {},
+  },
+};

x-pack/plugins/data_usage/public/app/components/charts.tsx

@@ -9,18 +9,21 @@ import { EuiFlexGroup } from '@elastic/eui';
 import { MetricTypes } from '../../../common/rest_types';
 import { ChartPanel } from './chart_panel';
 import { UsageMetricsResponseSchemaBody } from '../../../common/rest_types';
+import { useTestIdGenerator } from '../../hooks/use_test_id_generator';
 interface ChartsProps {
   data: UsageMetricsResponseSchemaBody;
+  'data-test-subj'?: string;
 }
 
-export const Charts: React.FC<ChartsProps> = ({ data }) => {
+export const Charts: React.FC<ChartsProps> = ({ data, 'data-test-subj': dataTestSubj }) => {
+  const getTestId = useTestIdGenerator(dataTestSubj);
   const [popoverOpen, setPopoverOpen] = useState<string | null>(null);
   const togglePopover = useCallback((streamName: string | null) => {
     setPopoverOpen((prev) => (prev === streamName ? null : streamName));
   }, []);
 
   return (
-    <EuiFlexGroup direction="column">
+    <EuiFlexGroup direction="column" data-test-subj={getTestId('charts')}>
       {Object.entries(data.metrics).map(([metricType, series], idx) => (
         <ChartPanel
           key={metricType}