Do not fetch truth twice when current_date == selected_as_of_date

[matthewcornell]

I noticed that when the component first loads, it calls the same truth API call twice: fetchDataUpdatePlot() calls fetchAsOfTruth() and then fetchCurrentTruth() even though the underlying dates are the initially the same (App.state.selected_as_of_date and App.state.current_date, respectively). This issue is for a fetchDataUpdatePlot() optimization that copies results from fetchAsOfTruth() (App.state.as_of_truth) to App.state.current_truth instead of calling fetchCurrentTruth().