Ava UI: Fix crash when clicking on a cheat's name (#5860)

* Fix crash

* Remove nullable

* Hide BuildId for child nodes

* Fix warning

* Fix charset

src/Ryujinx.Ava/UI/Models/CheatNode.cs

@@ -0,0 +1,57 @@
+using Ryujinx.Ava.UI.ViewModels;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.Linq;
+
+namespace Ryujinx.Ava.UI.Models
+{
+    public class CheatNode : BaseModel
+    {
+        private bool _isEnabled = false;
+        public ObservableCollection<CheatNode> SubNodes { get; } = new();
+        public string CleanName => Name[1..^7];
+        public string BuildIdKey => $"{BuildId}-{Name}";
+        public bool IsRootNode { get; }
+        public string Name { get; }
+        public string BuildId { get; }
+        public string Path { get; }
+        public bool IsEnabled
+        {
+            get
+            {
+                if (SubNodes.Count > 0)
+                {
+                    return SubNodes.ToList().TrueForAll(x => x.IsEnabled);
+                }
+
+                return _isEnabled;
+            }
+            set
+            {
+                foreach (var cheat in SubNodes)
+                {
+                    cheat.IsEnabled = value;
+                    cheat.OnPropertyChanged();
+                }
+
+                _isEnabled = value;
+            }
+        }
+
+        public CheatNode(string name, string buildId, string path, bool isRootNode, bool isEnabled = false)
+        {
+            Name = name;
+            BuildId = buildId;
+            Path = path;
+            IsEnabled = isEnabled;
+            IsRootNode = isRootNode;
+
+            SubNodes.CollectionChanged += CheatsList_CollectionChanged;
+        }
+
+        private void CheatsList_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            OnPropertyChanged(nameof(IsEnabled));
+        }
+    }
+}