do not add disappearing messages configuration to content message proto until the new design is enabled

SessionMessagingKit/Messages/Message.swift

@@ -65,6 +65,7 @@ public class Message: Codable {
     
     public func setDisappearingMessagesConfigurationIfNeeded(_ db: Database, on proto: SNProtoContent.SNProtoContentBuilder) throws {
         guard
+            DisappearingMessagesConfiguration.isNewConfigurationEnabled,
             let threadId: String = threadId,
             let disappearingMessagesConfiguration = try? DisappearingMessagesConfiguration.fetchOne(db, id: threadId)
         else { return }