Lists the collaborators (contacts and contact groups) that have been granted producer access to a webinar.

Results are scoped to what the authenticated user is allowed to see: account owners, managers, and the webinar's producers see all collaborators; everyone else sees an empty list.

Requires api token with one of the following permissions

Read all data

Tokens with the "Act with a team member's permissions" permission
(all:delegate_to_contact_permissions scope) can also be used. Requests
made with such a token are authorized using the permissions of the
contact assigned to the token.

An expiring access token
created with the all:delegate_to_contact_permissions scope and an
authorization granting the update permission on this webinar can also
be used; a token granted only show on the webinar lists no
collaborators.