[WinAppSDK] Attaching controls to the visual tree is 40x slower on MAUI than on bare WinUI

### Description

Attaching a deep tree of controls to the live tree is 40x slower on MAUI than on bare WinUI 3, for similar operations.

### Steps to Reproduce

Considering this code:
```csharp
private StackLayout MakeLayout()
{
var current = new StackLayout()
{
Children = { new Label() { Text = "Inner" } }
};

for (int x = 0; x < 99; x++)
{
var panel = new StackLayout();

panel.Children.Add(current);

current = panel;
}

return current;
}
```

Attaching the resulting layout to any parent (anything in the live visual tree) is costly:


The equivalent in WinUI:
```csharp
private StackPanel MakePanel()
{
var current = new StackPanel()
{
Children = { new TextBlock() { Text = "Inner" } }
};

for (int x = 0; x < 99; x++)
{
var panel = new StackPanel();

panel.Children.Add(current);

current = panel;
}

return current;
}
```

### Version with bug

Release Candidate 2 (current)

### Last version that worked well

Unknown/Other

### Affected platforms

Windows

### Affected platform versions

net6.0-windows10.0.19041

### Did you find any workaround?

None.

### Relevant log output

_No response_

Start with the provided MakeLayout reproduction and profile the operation of attaching its 99-level StackLayout tree to a live visual-tree parent on Windows. Compare the result with the equivalent WinUI StackPanel benchmark; done means identifying and addressing the reported performance gap, with measurements showing the slowdown is substantially reduced.

Written by the indexing model from the issue text.