Fix: leaf_level offloading breaks after delete_adapters (#12639)
* Fix(peft): Re-apply group offloading after deleting adapters
* Test: Add regression test for group offloading + delete_adapters
* Test: Add assertions to verify output changes after deletion
* Test: Add try/finally to clean up group offloading hooks
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Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>