Feat: SDK receive() should read messages after a SubmitError

[uri-99]

On the SDK's submit_multiple(), the receive() function will close the connection if the sender receives an error for any proof from the Batcher. This should be fixed, allowing the sender to keep on reading for messages since the following responses may be valid.

This enables a case of the last message received being an error, thus some sort of timeout should be implemented to avoid the connection being left hanged.