Revert "Create LegacyCollectionsAuthorizationHandler and start to re-implement old logic"

This reverts commit fbb19cdadd.

src/Core/Context/CurrentContext.cs

@@ -345,7 +345,6 @@ public class CurrentContext : ICurrentContext
                     && (o.Permissions?.DeleteAssignedCollections ?? false)) ?? false);
     }
 
-    // TODO: move into the auth handler now so that we can have separate implementations depending on feature flag
     public async Task<bool> ViewAssignedCollections(Guid orgId)
     {
         /*