Add boolean to toggle defaultLabelText changes on slice hover

[bronson-allen]

Currently, the default action is to change the defaultDataLabelText and defaultDataLabelValue to the data of the slice on hover. This functionality is disabled when the DonutChart has children, however. Adding children should not be the solution to toggling the hover on slice action.

Change:
Add an additional boolean value that allows you to toggle this hover functionality on or off. For specific cases where there is no relevant data associated with a slice and you want to hover over a slice without animation AND without updating the data label in the center of the chart.