[SBN read] Change client logging to be less aggressive

Currently ObserverReadProxyProvider logs a lot of information. There are states that are acceptable but ObserverReadProxyProvider still log an overwhelmingly large amount of messages. One example is that, if some NN runs an older version, the lack of getHAServiceState method in older version NN will lead to a Exception prints on every single call.

We can change them to debug log. This should be minimum risk, because this is only client side, we can always enable the log back by changing to DEBUG log level on client side.