Chart legend - always defaulting and not handling TSTool legend format specifiers

[smalers]

I tried to configure two population time series from different years of publication. I wanted to add 2020 in the legend for one and 2021 in the legend for another. However, the legend property seems to be hard-coded to the alias. See the following graph configuration file:

          "LegendFormat" : "%A (2021)",

county-population-graph-config.json

I think the Java code equivalent is the TS class formatLegend function.

It would be good if that method were fully enabled.

[Nightsphere]

The latest code was merged and pushed. I'll wait to close this until Steve confirms it's fixed.