Revert "Don't ignore parentId for playlists"

This reverts commit 98c6c34fbbcdb556873bdcdb577fbc55a296b650.

Jellyfin.Api/Controllers/ItemsController.cs

@@ -244,7 +244,8 @@ namespace Jellyfin.Api.Controllers
                 .AddAdditionalDtoOptions(enableImages, enableUserData, imageTypeLimit, enableImageTypes);
 
             if (includeItemTypes.Length == 1
-                && includeItemTypes[0] == BaseItemKind.BoxSet)
+                && (includeItemTypes[0] == BaseItemKind.Playlist
+                    || includeItemTypes[0] == BaseItemKind.BoxSet))
             {
                 parentId = null;
             }