`variant_object_construct`: Support array arguments

[friendlymatthew]

See:

datafusion-variant/test_files/variant_object_construct.slt

Lines 64 to 77 in f983e46

	# todo: uncomment when we support array cases
	# # Test 6: Construct objects from table data
	# query T
	# SELECT variant_pretty(
	# variant_object_construct(
	# 'name', json_to_variant('"' || name || '"'),
	# 'age', json_to_variant(CAST(age AS TEXT)),
	# 'active', json_to_variant(CAST(active AS TEXT))
	# )
	# ) FROM test_data ORDER BY id;
	# ----
	# {"name": ShortString(ShortString("Alice")), "age": Int32(30), "active": Bool(true)}
	# {"name": ShortString(ShortString("Bob")), "age": Int32(25), "active": Bool(false)}
	# {"name": ShortString(ShortString("Charlie")), "age": Int32(35), "active": Bool(true)}

[friendlymatthew]

Closed via eb0c899