[electrum] use ECPubkey in verify_message

Summary:
And rename the function to verify_message_with_address

This introduces a minor change in behavior: if pubkey_from_signature raises, we catch the error and return False, so garbage signatures will no longer cause an error to be raised, we will just see the verification fail.

Depends on D16350
Split out of D16301

Test Plan:

• test with the interactive signing and verifying tool in the wallet
• try electrum-abc --test-release-notification (or manually verify the signature data from releases.json)
• python test_runner.py

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D16351