fix: always use compressed public keys in signer config

[hstove]

The signer converts its private key to a Stacks address when looking up whether it is registered in a reward cycle. If the configured private key didn't have a compress_public flag (ie ending in 01), the public key wouldn't be compressed when generating the Stacks address. This could lead to the signer incorrectly thinking it isn't registered.

This PR also updates the check-config command to output the compressed public key.

Relates to:

• https://github.com/stacks-network/stacks-core/issues/4761

[BowTiedDevOps]

Fixes #4761

[hstove]

Rebased and ready for review 👍🏼