Crash on using clusterProperties

[westnordost]

While trying out how the clusterProperties work to properly document it, I noticed that it just crashes if one attempts to use it.

When I add in ClusterPointsDemo

clusterProperties = mapOf("range" to GeoJsonOptions.ClusterProperty("+", feature.get("current_range_meters")))

(and "current_range_meters" to (bike["current_range_meters"] ?: JsonNull), in readGbfsData to actually have that data in the geojson)

the Android app will just crash in native code.

Of course, MapLibre should not crash, but maybe it crashes because the API is not used in the expected manner?