[Fix][CI] Fix the CI import issue in test_quant_api.py

[Stonepia]

This is to fix the issue we found during the CI. There are issues like:

==================================== ERRORS ====================================
_____________ ERROR collecting test/quantization/test_quant_api.py _____________
ImportError while importing test module '/pytorch/ao/test/quantization/test_quant_api.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/conda/envs/venv/lib/python3.10/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
test/quantization/test_quant_api.py:17: in <module>
    from torch.ao.quantization.quantize_pt2e import convert_pt2e, prepare_pt2e
E   ModuleNotFoundError: No module named 'torch.ao.quantization.quantize_pt2e'

cc: @jerryzh168

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/ao/3539

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❌ 1 New Failure

As of commit e0abea6 with merge base 57432bd ():

NEW FAILURE - The following job has failed:

• Run Regression Tests / test-nightly (CUDA Nightly, linux.g5.12xlarge.nvidia.gpu, --pre torch --index-url https://downloa... / linux-job (gh)
  test/test_low_bit_optim.py::TestFSDP2::test_fsdp2

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