filter_spatial with point FeatureCollection

[VictorVerhaert]

Using filter_spacial with a FeatureCollection containing POINT's now returns a nested and unclear error:
OpenEO batch job failed: TypeError("'Point' object is not subscriptable")

Either a clearer error message should be provided, or the driver should support point feature collections for filter_spacial.

[soxofaan]

back-end side stack trace of this error FYI:

  File "/opt/venv/lib64/python3.8/site-packages/openeo_driver/ProcessGraphDeserializer.py", line 402, in convert_node
    process_result = apply_process(process_id=process_id, args=processGraph.get('arguments', {}),
  File "/opt/venv/lib64/python3.8/site-packages/openeo_driver/ProcessGraphDeserializer.py", line 1594, in apply_process
    return process_function(args=ProcessArgs(args, process_id=process_id), env=env)
  File "/opt/venv/lib64/python3.8/site-packages/openeo_driver/ProcessGraphDeserializer.py", line 1283, in filter_spatial
    geometries = MultiPolygon(polygons)
  File "/opt/venv/lib64/python3.8/site-packages/shapely/geometry/multipolygon.py", line 60, in __init__
    geom, n = geos_multipolygon_from_polygons(polygons)
  File "/opt/venv/lib64/python3.8/site-packages/shapely/geometry/multipolygon.py", line 202, in geos_multipolygon_from_polygons
    shell = ob[0]
TypeError: 'Point' object is not subscriptable