GeoJsonSource: withAttrLayers defaults to false, silently dropping nested properties

[MisterGC]

When using GeoJsonSource via the GeoJsonFolder datasource type, the withAttrLayers config option defaults to false (cli.cpp:236). This causes all object-typed GeoJSON properties to be silently dropped from the resulting mapget features.

For example, a GeoJSON feature with:

"properties": {
  "layer": {
    "RoadCharacteristicsLayer": {
      "FUNCTIONAL_ROAD_CLASS": { "attributeValue": { "functionalRoadClass": 5 } }
    }
  },
  "length": 25200
}

...only produces { "length": 25200 } in the mapget output. The entire layer object tree is lost.

This is confusing because there is no log warning about skipped properties, making it look like a bug rather than a configuration choice.

Suggested fix: Default withAttrLayers to true.