Delete obsolete split duckdb files
Fix for https://github.com/huggingface/datasets-server/issues/2053
Delete obsolete files for splits that no longer exist including `index.duckdb`
Delete obsolete split duckdb files: Fix for https://github.com/huggingface/datasets-server/issues/2053
Delete obsolete files for splits that no longer exist including `index.duckdb`