fix add contact page

Author: Trolldemorted

Signal-Windows/ViewModels/AddContactPageViewModel.cs

@@ -325,7 +325,7 @@ private async Task AddContact(string name, string number)
             };
             await Task.Run(() =>
             {
-                //TODO inform UI
+                App.Handle.SaveAndDispatchSignalConversation(contact, null);
             });
         }