[FA-misc] Fix issues with novel imports

FictionArchive.Service.NovelService/GraphQL/Mutation.cs

@@ -16,7 +16,7 @@ public class Mutation
 {
     [Error<InvalidOperationException>]
     [Authorize]
-    public async Task<NovelImportRequested> ImportNovel(string novelUrl, NovelUpdateService service)
+    public async Task<ImportNovelResult> ImportNovel(string novelUrl, NovelUpdateService service)
     {
         return await service.QueueNovelImport(novelUrl);
     }