FIX PEFT test changed error type (#46959)
In test_peft_from_pretrained_hub_kwargs, which loads a PEFT adapter
from a revision, we were checking for an OSError when the revision is
omitted. However, Transformers now raises a ValueError. The test is
thus changed to check for ValueError.
I haven't checked when exactly this behavior changed. As the PEFT
tests are marked as slow, they don't run on normal CI and this change
hasn't been caught.
