Invite a guest user by email. An invitation email is sent to the accepter; the invitation is valid for 72 hours by default.
Requires guest invitations to be enabled for your SecureCloud instance and the can_invite_guest permission of the user's role; otherwise 403 is returned.
Fails with 400 if the email address is invalid or blocked, already invited by you, belongs to an active account, or belongs to an inactive non-guest account.