Comment 2 for bug 1859708

Originally I had planned to deprecate this interface with the work in bug 1846354, but I was thinking it was just a view of what patrons saw in the Message Center and not an actual staff interface, so I left it alone after realizing this. Giving it another look, most of the functionality here is redundant with the new development, but there is one side effect with that work that affects this interface: it can list deleted user messages whereas the main interface does not. I still think it should go away. However, we will need another re-implementation of the old Messages interface in the future to go from AngularJS to Angular.