Cluster counts need to be updated when features are unselected

Issue: When a user un-checks an item in the map legend, cluster count numbers don't update, but need to.

Progress update. It appears filtering on a data source before clustering isn't possible with Mapbox. See the following discussions;

• Support preclustering filtering mapbox/supercluster#11
• Add a filter option for GeoJSON sources mapbox/mapbox-gl-js#9864
• Cluster counts are wrong when filters are enables mapbox/mapbox-gl-js#7887

Based on what I've read and tried through experimentation, one possible solution would be to store a copy of the geojson in the browser's memory, and when a user makes a change to the map, the a copy of the original data source is updated (e.g. features are filtered) and the data source used by the map/clusters/layers is updated.

@Noznoc any ideas on how to solve this?

[Noznoc]

From my experience with clustering, I would have the points stored in the browser's memory for retrieval and rendering. Considering the point sizes are not that big, we could do this, but not sure how much effort this would take versus just waiting until we have an appropriate database set up.