Automatically generate `.rcpsnap` files when a CI parity check fails

# Summary

To aid in debugging and regression testing, our CI should be designed to automatically generate `.rcpsnap ` files whenever a parity check fails. This feature ensures that any mismatch between expected and actual RPC responses is immediately captured for inspection.

# Requirements

The captured snapshot files should be uploaded in `spaces/forest-snapshots/debug/`.

# Motivation

It would save everyone from the time-consuming process of reproducing error locally; downloading a recent similar snapshot, running the Forest and Lotus clients, potentially backfilling index, generating `.rcpsnap` files, manually uploading them, and more.