address upscroll wonkiness on beeswarm

[cnell-usgs]

On mobile, the upscroll for the beeswarm gets off in the transition between the 100% training ANN data and the RMSE dot that moves around. The links from the error chart appear early (step_rmse+3) when they shouldn't be seen until step_error_obs, and may have their own strength that's counteracting forceCollide? It's possible this is simply due to a step numbering issue on mobile, where the forces are changing out of sync with the data in view.

[cnell-usgs]

In general, on upscroll, forces and other attribute transitions should be linked to this.active.step-1 due to the way events are triggered