[Dinov2] Enable device_map="auto" support (#38487)
* Fix: resolve import order and duplicate import (ruff I001, F811)
* Format: clean up Dinov2 test file with ruff formatter
* Add _no_split_modules = ['Dinov2Layer'] to enable device_map='auto'
* Revert dinov2_with_registers _no_split_modules to original state
* Remove redundant device_map test as suggested
* Remove unused import after deleting test
* removed import torch and the redundant test function
* Update tests/models/dinov2/test_modeling_dinov2.py
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Co-authored-by: Marc Sun <57196510+SunMarc@users.noreply.github.com>
