Re-add IsMovie

Jellyfin.Api/Controllers/LibraryController.cs

@@ -732,6 +732,9 @@ namespace Jellyfin.Api.Controllers
             }
             else
             {
+                // For non series and movie types these columns are typically null
+                isSeries = null;
+                isMovie = null;
                 includeItemTypes.Add(item.GetType().Name);
             }
 
@@ -739,6 +742,7 @@ namespace Jellyfin.Api.Controllers
             {
                 Limit = limit,
                 IncludeItemTypes = includeItemTypes.ToArray(),
+                IsMovie = isMovie,
                 SimilarTo = item,
                 DtoOptions = dtoOptions,
                 EnableTotalRecordCount = !isMovie ?? true,