Gradient colors needs a midpoint setting

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The recent gradient color addition to Analyzer has the potential to eliminate the need for setting up a bunch of color rules for variance colors, but it needs the ability to set a midpoint value like the heatmap color setting on table cards. Currently the gradient colors are relative to the bars displayed on a chart including when filters are applied.

If you have a bar chart with a range of values from positive to negative and set gradient colors with green/red upper and lower ranges, it seems to be pretty good at using zero as the midpoint. But if you apply a filter that returns only the bars with a negative value, it uses the entire upper and lower gradient selection. This results in the largest negative number turning green when all the negative bars should remain red.