Suppress Obsolete warning in TopicViewModelLookupService

Since the `ListTopicViewModel` has been marked as deprecated (11c606f), it will get a warning when referenced. This is a good thing. But as this is already known and accounted for, we want to disable that warning when registering the view model in the `TopicViewModelLookupService`; this will be removed once the deprecated class is removed.

Author: JeremyCaney

OnTopic.ViewModels/TopicViewModelLookupService.cs

@@ -50,10 +50,18 @@ public TopicViewModelLookupService(IEnumerable<Type>? types = null) : base(types
       \-----------------------------------------------------------------------------------------------------------------------*/
       TryAdd(typeof(ItemTopicViewModel));
       TryAdd(typeof(ContentItemTopicViewModel));
-      TryAdd(typeof(ListTopicViewModel));
       TryAdd(typeof(LookupListItemTopicViewModel));
       TryAdd(typeof(SlideTopicViewModel));
 
+      /*------------------------------------------------------------------------------------------------------------------------
+      | Add obsolete types
+      >-------------------------------------------------------------------------------------------------------------------------
+      | These will be removed in the next major version of OnTopic.
+      \-----------------------------------------------------------------------------------------------------------------------*/
+#pragma warning disable CS0618 // Type or member is obsolete
+      TryAdd(typeof(ListTopicViewModel));
+      #pragma warning restore CS0618 // Type or member is obsolete
+
       /*------------------------------------------------------------------------------------------------------------------------
       | Add support types
       \-----------------------------------------------------------------------------------------------------------------------*/