OperatorExportToGeoJson doesn't export the spatial reference.

To reproduce, run OperatorExportToGeoJson.local().execute with exportFlags = GeoJsonExportFlags.geoJsonExportDefaults, spatial reference wkid = 3857, and the following geometry:

{"rings":[[[1600,9082],[1600,8682],[1100,8682],[1100,9082],[1600,9082]]]}

The output looks like this:
{"type":"Polygon","coordinates":[[[1600.0,9082.0],[1600.0,8682.0],[1100.0,8682.0],[1100.0,9082.0],[1600.0,9082.0]]]}

It really would be better to have the spatial reference in the output especially since it is an input parameter.