feat: Add module_call_graph to handle output spec

[peri044]

Description

• This PR adds module_call_graph to preserve the output spec obtained from the graph module.
• This will let exported program know what the output_spec is during it's construction and ensure the verifier operates properly.
• This PR should go after https://github.com/pytorch/pytorch/pull/120361 so that the codegen of the partitioned module is populated correctly to add pytree flatten/unflatten nodes accordingly

Type of change

Please delete options that are not relevant and/or add your own.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist:

• [x] My code follows the style guidelines of this project (You can use the linters)
• [x] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas and hacks
• [ ] I have made corresponding changes to the documentation
• [x] I have added tests to verify my fix or my feature
• [x] New and existing unit tests pass locally with my changes
• [ ] I have added the relevant labels to my PR in so that relevant reviewers are notified