remove usage of Code::Identity in core/src/peer_id.rs

[jmmaloney4]

Description

Remove usage of Code::Identity in core/src/peer_id.rs, to fix #3276.

Links to any relevant issues

#3276

Open Questions

I'm unsure how to test this change thoroughly. I couldn't get cargo test to compile, even on the master branch.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[rkuhn]

This will break lots of code without alerting maintainers through compile errors, i.e. this is really bad: Actyx for example only supports ed25519 and then makes use of the fact that the public key can be recovered from the PeerId.

Changing the bit format of PeerId (for the same key) also is a network breaking change, so such a proposal should come with a thorough analysis of the intended and unintended effects as well as a migration plan. And if the only benefit is to avoid a deprecated internal function, then I don’t think this is worth it.

[thomaseizinger]

Thanks for commenting @rkuhn! There was a misunderstanding on the original issue that I've hopefully been able to clarify! :)

[rkuhn]

Yes, thanks!

[mergify]

This pull request has merge conflicts. Could you please resolve them @jmmaloney4? 🙏

[thomaseizinger]

Closing in favor of #3514.