Fix for DelayedVector that are not geojson format.

[EmileSonneveld]

Found while fixing typings with mypy
Related Open-EO/openeo-geopyspark-driver#793

[EmileSonneveld]

@copilot review without making changes

[Copilot]

@copilot review without making changes

I found one substantive issue: DelayedVector.as_geodataframe() currently builds a GeoDataFrame from self.geometries only, so feature properties are dropped. As a result, to_save_result(DelayedVector(...), format="parquet") writes only the geometry column, while id and pop from FeatureCollection02.json are lost. That matches the TODO in tests/test_save_result_parquet.py where the delayed-vector path currently ends up with shape (2, 1) instead of preserving the attributes like the direct gpd.read_file(...) path does.

[EmileSonneveld]

@JeroenVerstraelen I found this while checking with mypy. This makes sure the 'data' used in the object that is returned