As an internal Ideas user, I should be able to initiate private chats with the Idea Creator. Merged

The new Private Comment feature is great, but it is only available for the Ideas portal user to initiate conversations with Internal users. We should be able to work the other way around as well - Internal users can reach out to the Creator via a private threaded chat as well. Otherwise we're reliant on asking the end user to 'open a private chat thread' which is a poor user experience.