Bug clicking in region map on empty regions

[markov00]

If you create a region map, add aggregations and than click on region that doesn't have data, Kibana will throw the following error:

Uncaught TypeError: Cannot read property '0' of undefined
    at Object.addFilter (vis.js:145)
    at ChoroplethLayer.<anonymous> (region_map_visualization.js:264)
    at ChoroplethLayer.EventEmitter.emit (events.js:81)
    at e.<anonymous> (choropleth_layer.js:139)
    at e.fire (leaflet.js:5)
    at e._fireDOMEvent (leaflet.js:6)
    at e._fireEvent (leaflet.js:8)
    at e._onClick (leaflet.js:8)
    at HTMLCanvasElement.h (leaflet.js:6)

The select/click event trigger the addFilter function with a rowIndex of -1 that will throws the error when the API.events.addFilter method try to find the correct row in the data table.

@elastic/kibana-visualizations

This bug is not yet released and would cause a regression from 6.3.0 if not fixed.