[APM] Charts: Disable showing values on series labels (#127646)

Author: younesmln

x-pack/plugins/apm/public/components/shared/charts/timeseries_chart.tsx

@@ -129,7 +129,6 @@ export function TimeseriesChart({
             tooltip: { visible: true },
           }}
           showLegend
-          showLegendExtra
           legendPosition={Position.Bottom}
           xDomain={xDomain}
           onLegendItemClick={(legend) => {