DevTools not updating tree

[grokys]

#4533 has broken DevTools in that nodes aren't getting updated when the logical/visual tree gets updated:

[grokys]

This seems to be because TreeNodeCollection adds CollectionChanged handlers direct to the inner AvaloniaList<T>:

Avalonia/src/Avalonia.Diagnostics/Diagnostics/ViewModels/TreeNodeCollection.cs

Lines 36 to 40 in 9baf4ef

	public event NotifyCollectionChangedEventHandler CollectionChanged
	{
	add => _inner.CollectionChanged += value;
	remove => _inner.CollectionChanged -= value;
	}

Meaning that when the event is raised the sender will be for the inner collection. However CollectionChangedEventManager tries to use sender as a key to look up the collection:

Avalonia/src/Avalonia.Controls/Utils/CollectionChangedEventManager.cs

Line 123 in 9baf4ef

if (sender is INotifyCollectionChanged incc && _entries.TryGetValue(incc, out var listeners))

Which is then not found because the sender isn't the collection that the event was registered with.