remove hook for bnb 4-bit #5216

Job	Run time
run-tests (latest, test_prod)	1m 54s
run-tests (latest, test_core)	3m 10s
run-tests (latest, test_cli)	2m 42s
run-tests (latest, test_big_modeling)	2m 37s
run-tests (latest, test_deepspeed)	2m 46s
run-tests (latest, test_fsdp)	2m 38s
run-tests (latest, test_example_differences)	2m 36s
run-tests (latest, test_checkpoint_step)	4m 8s
run-tests (latest, test_checkpoint_epoch)	4m 4s
run-tests (latest, test_rest)	8m 55s
run-tests (minimum, test_prod)	2m 57s
run-tests (minimum, test_core)	4m 10s
run-tests (minimum, test_cli)	3m 47s
run-tests (minimum, test_big_modeling)	3m 40s
run-tests (minimum, test_deepspeed)	3m 47s
run-tests (minimum, test_fsdp)	3m 33s
run-tests (minimum, test_example_differences)	3m 34s
run-tests (minimum, test_checkpoint_step)	5m 25s
run-tests (minimum, test_checkpoint_epoch)	5m 0s
run-tests (minimum, test_rest)	10m 48s
	1h 22m 11s

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