[shimizust]

Summary

With transformers >= 4.52.0, there was some refactoring of gemma3 model code. Patching should still work for previous transformers version, but gemma3 tests won't pass for older transformers versions. Not sure we want to maintain that logic in the tests.

For reference:

• Before (transformers <=4.51.3):

Gemma3ForConditionalGeneration
 - language_model (Gemma3ForCausalLM)
    - model (Gemma3TextModel)
       - layers/norm/etc.

• After:

Gemma3ForConditionalGeneration
- model (Gemma3Model)
   - language_model (Gemma3TextModel)
      - layers/norm/etc.
- language_model (for backwards-compatibility, points to model.language_model (Gemma3TextModel))

Fixing part of #729

Testing Done

Gemma3 monkey patch tests pass

pytest test/transformers/test_monkey_patch.py::test_apply_liger_kernel_to_instance_for_gemma3_conditional_generation
pytest test/transformers/test_monkey_patch.py::test_apply_liger_kernel_to_instance_for_gemma3_text 

• Hardware Type:
• run make test to ensure correctness
• run make checkstyle to ensure code style
• run make test-convergence to ensure convergence