Revert "[Ray Dataset] fix the type infer of pd.dataframe (when dtype is object)" (#25809)
Revert "[Ray Dataset] fix the type infer of pd.dataframe (when dtype is object)" (#25809)

This reverts commit f61f60f70857888751c214d8ec280b85aeeb5932.
ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray,ray-project/ray