GlChartLegend passes invalid type prop to GlChartSeriesLabel

!2714 (merged) caused some downstream test failures in gitlab!83745 (merged), with the errors like:

  ● Stacked column chart component › when graphData is present › chart is rendered
    Unexpected call of console.error() with:
    [Vue warn]: Error in nextTick: "Error: Unexpected call of console.error() with:
    [Vue warn]: Invalid prop: custom validator check failed for prop "type".
    found in
    ---> <GlChartSeriesLabel>
           <ChartLegend>
             <GlStackedColumnChart>
               <Anonymous>
                 <Root>"

The type being passed is bar, which is the chart's type, rather than the series' label type, which is "supposed" to be solid or dashed. This suggests to me that the data flow between GlStackedColumnChart, ChartLegend and GlChartSeriesLabel is not quite right.

The fix may be as simple as removing the type prop passed here and here, but then how would the dashed series label ever be rendered by the legend?