TSV: Flag data as provisional

[SRGDamia1]

Currently there's a flag at the top of every spark line noting that all data is provisional. TSV has no such warning. We should add one, especially if there are going to be more statistics or other analysis displayed there.

The flag should be somewhere near the plot title and potentially also in a pop-up or click-required hover presented to the user on entering TSV.

@dbressler75