Renaming split-names response to splits
Fix content response name in split_names_from_streaming and split_names_from_dataset_info from "split_names" to "splits" so that it is consistent with the response of splits worker 
Renaming split-names response to splits: Fix content response name in split_names_from_streaming and split_names_from_dataset_info from "split_names" to "splits" so that it is consistent with the response of splits worker 