Discard automatic redirections in Discussion/DiscussionContext pages

As part of DISCUSSION-45 we introduced the capability to add automatic redirections for any discussion technical page. The goal was primarily to fix usability bugs, in particular in case of mentions when people are led to the Message page.
But we implemented it not only for Message technical pages, but for any technical page, including Discussion and DiscussionContext.

Right now I think we should rollback the changes performed for those specific pages: in some cases, mainly for maintenance and resolution of problems reasons, it can be useful for admins to access those pages, and the redirection is creating friction for that. For standard user, it shouldn't have any impact: AFAIK only the Message pages are relevant to be accessed and for those we should keep the redirection object.