Charts - add unique IDs to labels

[dlabrecq]

Need to ensure chart labels are assigned unique IDs.

For ChartAxis, we only output unique IDs for tick labels. Victory outputs a default id="axis-axisLabel-0" ID for both x and y axis labels, which results in duplicates.

As a workaround, it may be possible to override axisLabelComponent of ChartAxis and provide a custom name property.