Layer timeline - Show keyframes of collapsed groups

Profile editor - Don't reload UI elements on undo/redo if there's nothing to undo/redo
Layer properties - Properly show/hide properties

src/Artemis.Storage/Entities/Profile/LayerEntity.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Text.Json.Serialization;
 using LiteDB;
 
 namespace Artemis.Storage.Entities.Profile