[FIX](Pie AllNullsOrZero) Regression caused in Pie chart caused by previous commit, for feature [ANALYZER-1711].
* If the first category had a null or zero value the InvalidDataException would be thrown, even if a subsequent category had a non-null or non-zero value.
* When in a multi-chart, the first small chart throwing the exception would cause the whole chart to fail: the exception is caught at the root chart. Now, when in multi-charts, the exception is not thrown, resulting in a blank Pie plot.