remove near_crypto::PublicKey in favor of near_sdk::PublicKey

[DSharifi]

Background

We'd like to remove the near_crypto::PublicKey type from our codebase as we already depend on near_sdk::PublicKey and want to avoid awkward conversions between the two types.

Acceptance Criteria

• Remove near_crypto dependency and replace all near_crypto::PublicKey usage with near_sdk::PublicKey.

Resources & Additional Notes

No response

[pbeza]

I’m all for unifying things and sticking to near_sdk::PublicKey. I doubt introducing two different types for the same concept was intentional (and even if it was, it can probably be unified anyway) — most likely just a coincidence — but happy to be proven wrong.

[DSharifi]

I removed the "[UP FOR DISCUSSION]" prefix, as it seems there is a consensus to go for a unification.

[DSharifi]

Only use case I find that we depend on is the in memory signer, near_crypto::Signer and near_crypto::InMemorySigner to call the method sign:

mpc/node/src/indexer/tx_signer.rs

Line 64 in b89d108

let signature = self.signer.sign(tx_hash.as_ref());

This method is just an abstraction over the industry standard crypto crates we already depend on, ed25519_dalek and secp256k1:
https://github.com/near/nearcore/blob/master/core/crypto/src/signature.rs#L345-L365