Update logic related to verifyLivenessConditionForRegisteredChains

[ishantiw]

Description

Improve util functions based on the latest update in LIP0053

def verifyLivenessConditionForRegisteredChains(ccu: Transaction) -> None:
    if len(ccu.params.certificate) > 0 and len(ccu.params.inboxUpdate) > 0:
        certificate = decode(certificateSchema, ccu.params.certificate)
        timestamp = timestamp of the block including ccu
        if len(ccu.params.inboxUpdate) > 0 and timestamp - certificate.timestamp > LIVENESS_LIMIT / 2:
            raise Exception(f"The first CCU with a non-empty inbox update cannot contain a certificate older than {LIVENESS_LIMIT / 2} seconds.")

Acceptance Criteria

• Should have unit test

Additional Information

• Related PR Update Interoperability LIPs lips#148
• Related LIP https://github.com/LiskHQ/lips/blob/main/proposals/lip-0053.md