Make atnotification->decrypted_value point to atnotification->value when it is a non-encrypted notification

[JeremyTubongbanua]

The way we currently handle non-encrypted notifications in monitor is that monitor_read populates atnotification->value to store the value, since no decryption is needed. Therefore, atnotification->decrypted_value remains null.

The proposed change is to have atnotification->decrypted_value point to atnotification->value, since it is non-encrypted anyways. This is a developer experience change.