Hide the content type selection dropdown in documentSet edit page

Question

I try to hide the content type dropdownlist from the document set edit form. I can successfully hide the my custom columns using the following script but cannot hide the content type dropdownlist.

Here is the code I use , for the complete code please see here.

$listField = $list.Fields.GetField(“Content Type”)
$listField.ShowInEditForm = $false
$listField.ShowInNewForm=$false
$listField.Update()