Remove UI theme from plotly express model

[mattrunyon]

As part of themeing work, we're moving the response to theme changes to the Chart component instead of anybody using the chart component needing to respond to theme changes.

In PlotlyExpressChartModel, we should remove the ChartTheme passed in and modify applyColorwayToData to just remove the colors from the traces if they match plotly's template (and the user did not explicitly set the template). This should let the Chart component apply the UI theme but still override from plotly because the colors in the series override the template