Unable to find supplier portal user account through REST API

Summary:

For my application I need to fetch the contact detail of the supplier like first name, last name, Administrative Contact, phone, fax, email along with supplier portal user account through fusion rest API. I am using the below API to get the contact details, however I cannot find any attribute like supplier portal user account. Is there any other API available? If available how to check if the supplier has user account through API

/fscmRestApi/resources/11.13.18.05/suppliers/{SupplierId}/child/contacts

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