Remove minimum height for zero-values in bar chart

Fixes #201.

This is really a UX issue.

Previously, if any datapoint was a zero-value, it would still be visible on the chart, making it seem it has non-zero data.

P.S. I wasn't able to run the contribution steps locally, so I have no idea how to rebuild the distribution(s). That might need a separate commit/PR.

src/js/utils/constants.js

@@ -68,7 +68,7 @@ export const AXIS_DATASET_CHART_TYPES = ['line', 'bar'];
 export const AXIS_LEGEND_BAR_SIZE = 100;
 
 export const BAR_CHART_SPACE_RATIO = 0.5;
-export const MIN_BAR_PERCENT_HEIGHT = 0.01;
+export const MIN_BAR_PERCENT_HEIGHT = 0.00;
 
 export const LINE_CHART_DOT_SIZE = 4;
 export const DOT_OVERLAY_SIZE_INCR = 4;