Default to processor count concurrent scan instead of 2 * processor count (#11569)

MediaBrowser.Controller/Entities/Folder.cs

@@ -594,7 +594,7 @@ namespace MediaBrowser.Controller.Entities
             }
 
             var fanoutConcurrency = ConfigurationManager.Configuration.LibraryScanFanoutConcurrency;
-            var parallelism = fanoutConcurrency > 0 ? fanoutConcurrency : 2 * Environment.ProcessorCount;
+            var parallelism = fanoutConcurrency > 0 ? fanoutConcurrency : Environment.ProcessorCount;
 
             var actionBlock = new ActionBlock<int>(
                 async i =>