fix: ValueError when using FromOriginalModelMixin in subclasses #8440 (#8454)
* fix: ValueError when using FromOriginalModelMixin in subclasses #8440
(cherry picked from commit 92859978436acf844760fc0e992165b489d0180a)
* Update src/diffusers/loaders/single_file_model.py
Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>
* Update single_file_model.py
* Update single_file_model.py
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Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>