registerLastDeviceRecoveryKey
abstract suspend fun registerLastDeviceRecoveryKey(address: DeviceAddress, registration: LastDeviceRecoveryKeyRegistration, signer: ServerRequestSigner)
Registers the user's last-device recovery public key (docs/last-device-recovery.md): PUT /v1/devices/{user}/{device}/last-device-recovery/key for address, signed with address's registered device authentication key. Registering the same key again is harmless. Throws SecureMessageTransportException.LastDeviceRecoveryKeyRejected (SecureMessageTransportException.RecoveryKeyFailure.CONFLICT if the user has another recovery key) or SecureMessageTransportException.AuthenticationFailed.