remove plotted point from the end of the truth data line and so it doesn't show up in tooltip

[nickreich]

Note that the point that we have added to manufacture the full polygon that originates from the last observed datapoint should not be present in the tooltip when hovering on that point, as it isn't part of the forecast. Ideal behavior would be:

• there should be a line from the end of the truth data to the end of the prediction points, going through each point. This line already exists in the viz
• There should only be actual points at the "point" prediction values, but there should not be a colored point at the "manufactured" point at the last truth value.
• The tooltip should show the point estimates for all values of the truth data (it does this already), and for the forecasted points that are shown (it does this already), but not for the initial ghost point of the models (this would need to be changed).

[nickreich]

Seems like this is sort of fixed in the latest build, but also now there are duplicate numbers showing in the tooltip: