Only allow Compose field layout option on node entities.
I've removed the actual field_layout Compose option on non-node entities.
Add a check to the original compose_form_alter() if() check to ensure $form_id == 'node_page_edit_form' so we don't do the form alter on non-node entities if the Compose field_layout option had previously been selected. This is just a fail-safe and does load the libraries and templates still, so it looks a bit funny, but loads and works.