[DataLoader] Make `batch` DataPipe sensitive to unbatch_level argument (#60672)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/60672
Test Plan: Imported from OSS
Reviewed By: mruberry
Differential Revision: D29461086
Pulled By: VitalyFedyunin
fbshipit-source-id: efc6b3b567323defe64d3f1b30a5708107e62dd4
