BigValue: Updated test dashboard and made some chart sizing tweaks (#21616)

packages/grafana-ui/src/components/BigValue/BigValueLayout.tsx

@@ -363,6 +363,8 @@ export class StackedWithChartLayout extends BigValueLayout {
 
     // make title fontsize it's a bit smaller than valueFontSize
     this.titleFontSize = Math.min(this.valueFontSize * 0.7, this.titleFontSize);
+    // make chart take up onused space
+    this.chartHeight = height - this.titleFontSize * LINE_HEIGHT - this.valueFontSize * LINE_HEIGHT + height * 0.05;
   }
 
   getValueAndTitleContainerStyles() {