Add geometry collection as children of unknown geometry array #2176

Job	Run time
build-benchmarks	3m 34s
check-features-with-external-dependencies (-F gdal -F gdal/bindgen)	40s
check-features	19s
check-features-with-external-dependencies (-F geos)	18s
Lint and Test	7m 39s
check-features (-F csv)	21s
check-features-with-external-dependencies (-F proj)	38s
check-features (-F flatgeobuf)	16s
check-features (-F flatgeobuf_async)	37s
check-features (-F ipc_compression)	28s
check-features (-F parquet)	27s
check-features (-F parquet_async)	25s
check-features (-F parquet_compression)	25s
check-features (-F polylabel)	29s
check-features (-F postgis)	1m 14s
check-features (-F rayon)	27s
	18m 17s

Provide feedback