Remove deprecated setZoneAssignments

[mapmeld]

Mentioned this on Slack - now that we moved to an event listener, setZoneAssignments is only called by the zone picker. We don't think this is necessary anymore now that the mouse exiting the map should apply the changes.

The calls were added to the picker in this commit and PR:
8dc9328
#129 (likely copying the Picker)

[nofurtherinformation]

Hey @mapmeld ! Thanks for this!

I reviewed and realized that the addition of zone updates within mapStore.selectMapfeatures was an error I introduced. It works and keeps the state highly synced with the map, but causes some performance and excess request issues.

I think the right way to handle zone updates (for now at least) is to only mutate the accumulatedGeoids set and handle any map rendering and tile logic (eg. clientside population) and then at the end of a paint event update the zone assignments.. This direction made more sense in the population chart enhancements and I think will simplify undo/redo in terms of number of events firing off.