Remove deepcopy override from ExportedProgram (#106578)
Summary: When we do a deep copy of the ExportedProgram because of the custom deep copy override the graph metadata (graph.meta) is failing to be copied over. This can be fixed but overall i don't see a need for a custom deepcopy in ExportedProgram and thus trying to get rid of it.
Test Plan: CI
Differential Revision: D48043723
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106578
Approved by: https://github.com/JacobSzwejbka
