Downloads chart: Avoid division by zero in percentage mode in the case of zero total downloads (#8595)

Author: szakarias

pkg/web_app/lib/src/widget/downloads_chart/widget.dart

@@ -356,7 +356,9 @@ void drawChart(
     final List<(double, double)> lineCoordinates = <(double, double)>[];
     for (int week = 0; week < values.length; week++) {
       final value = displayMode == DisplayMode.percentage
-          ? values[week][versionRange] * 100 / totals[week]
+          ? (totals[week] == 0
+              ? 0 //Avoid division by zero, and return zero
+              : values[week][versionRange] * 100 / totals[week])
           : values[week][versionRange];
 
       if (displayMode == DisplayMode.unstacked) {