Improve ScreenReaderSummary descriptions

[nickofthyme]

The current ScreenReaderSummary Component does not account for small multiples or summarizing data of any chart type other than Goal.

elastic-charts/packages/charts/src/components/accessibility/screen_reader_summary.tsx

Lines 37 to 50 in c433d8c

	const ScreenReaderSummaryComponent = ({
	a11ySettings,
	chartTypeDescription,
	goalChartData,
	goalChartLabels,
	}: ScreenReaderSummaryStateProps) => {
	return (
	<div className="echScreenReaderOnly">
	<ScreenReaderLabel {...a11ySettings} goalChartLabels={goalChartLabels} />
	<ScreenReaderDescription {...a11ySettings} />
	<ScreenReaderTypes {...a11ySettings} chartTypeDescription={chartTypeDescription} goalChartData={goalChartData} />
	</div>
	);
	};