[quant][graphmode][fx] Separate handling Copy operator to a helper function (#54644)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54644
Previously we special case copy operator in normal insert observer code, this PR tries to split the
special case logic to a separate function and keep the rest of the code clean.
Test Plan: Imported from OSS
Reviewed By: vkuzo
Differential Revision: D27314678
fbshipit-source-id: d36870ceb3717bc01eaeaa6f3f1532ad562cbaf1
