[fix] use non-inplace for insert observer pass (#34190)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34190
inplace modification of ClassType might affect other tests, so we want to do non-inplace modifications.
Actually the inplace argument will be removed soon.
Test Plan:
ci
Imported from OSS
Differential Revision: D20451765
fbshipit-source-id: e87ad528c4e7f84f5774b94a8e3e85568269682d
