Search for nested data
Duckdb does support indexing nested data so we're all good on that side already.
Therefore I simply improved the indexable column detection to check for nested data.

The old code used to index all the columns as long as there is at least one non-nested string column though, so we just need to refresh the datasets with the "no indexable columns" error.

Close https://github.com/huggingface/datasets-server/issues/1710
Search for nested data: Duckdb does support indexing nested data so we're all good on that side already.
Therefore I simply improved the indexable column detection to check for nested data.

The old code used to index all the columns as long as there is at least one non-nested string column though, so we just need to refresh the datasets with the "no indexable columns" error.

Close https://github.com/huggingface/datasets-server/issues/1710