Changelog:
1. When we run into an operation we didn't proxy, we end up emitting fake constants. We error under a config and we disable the config for some internal users. The reason we want to error is this signals a coverage problem we need to address but at the same time, we don't wnat to be disruptive to already working flows.
2. Previous attribute mutation detection logic in non-strict didn't account for nested module structure. This fixes silent incorrectness issue of exporting esm and qwen in non-strict and some torchbench models like levit_128 and demucs.
3. Previous logic didn't work on the cases where we mutate a container attribute as the previous approach used to pytree over old and new attributes resulting in length mismatch. We gracefully handle this now.
Differential Revision: [D83673054](https://our.internmc.facebook.com/intern/diff/D83673054)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/164372
Approved by: https://github.com/avikchaudhuri