[Feature]: create secp256r1 public key from exported key bytes

[gokhan-oner]

Summary

Ability to create secp256r1.PubKey from exported byte[]

Problem Definition

There's no (easy) way to verify a signature only using message, signature & address when using secp256r1 key pair. for secp256r1, recovery option can be used ( via github. com/ decred/ dcrd/ dcrec/ secp256k1/ v4/ ecdsa ) but for secp256r1, not possible ( no built-in functionality). Even with publicKey bytes encrypted & shared, there's no constructor, similar to secp256k1.PubKey that help constructing publicKey from bytes!

Proposed Feature

This is related to #19285, seems closed as completed but I don't see any constructor to create secp256r1 public keys from exported bytes ( tecnically from pubKey.Bytes(). Is it implemented or any plan to implement, or any example to refer? Due to ecdsaPK unexported byte, its not possible to convert an ecdsa.PubKey to secp256r1.pubKey