[functional collecitve] don't import torchdynamo when running torchdeploy (#120900)
Summary: Importing torchdynamo in `functional_collective_impl.py` seems to break loading of torchdeploy models.
Test Plan: CI
Differential Revision: D54355011
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120900
Approved by: https://github.com/fegin
