Prevent tree expansion blocking render

LANCommander/Components/FileManagerComponents/FileManager.razor

@@ -292,6 +292,8 @@
             var directory = (FileManagerDirectory)args.Node.DataItem;
 
             foreach (var child in directory.Children)
+            {
+                await Task.Run(() =>
                 {
                     var paths = Directory.EnumerateDirectories(child.Path, "*", new EnumerationOptions
                         {
@@ -301,6 +303,7 @@
                         });
 
                     child.PopulateChildren(paths);
+                });
             }
         }
     }