Modern FolderBrowserDialog still shows the New Folder button when ShowNewFolderButton is false

### .NET version

.NET 11.0.100-preview.7.26365.114

### Did it work in .NET Framework?

Yes

### Did it work in any of the earlier releases of .NET Core or .NET 5+?

No, it reproes after introduced modern FolderBrowserDialog

### Issue description

The FolderBrowserDialog.ShowNewFolderButton property does not appear to take effect.
When ShowNewFolderButton is set to **false**, the New Folder button is still displayed in the folder selection dialog.

### Steps to reproduce

1. Create a WinForms .NET application.
2. Add FolderBrowserDialog and Button to form designer
3. Add the following code:
```
using System.Windows.Forms;

private void button1_Click(object sender, EventArgs e)
{
using FolderBrowserDialog dialog = new FolderBrowserDialog();

dialog.ShowNewFolderButton = false;
dialog.ShowDialog();
}
```

3. Run the application.
4. Open the FolderBrowserDialog.

Start with the WinForms FolderBrowserDialog implementation and trace how ShowNewFolderButton is applied when ShowDialog is called. Reproduce the issue in a WinForms .NET application using the code and steps provided, then verify that setting the property to false hides the New Folder button.

Written by the indexing model from the issue text.