Retrieves information about which recipients can view specific documents in a package during a Signing Ceremony.
The response is a Document Visibility object that contains a list of configurations. Each configuration has:
(1) the Document ID of a specific document; (2) a list of Role IDs of the signers who can view the document.
Note that: Documents not in the Document Visibility object are visible to all recipients. The Package Owner can
always see all documents in the package, regardless of its Document Visibility configuration.