Update an existing list.
Only the fields listed below can be changed; any other field sent in the list object is ignored. Fields that are omitted keep their current value. name cannot contain HTML, and for lists on the email channel both sender_url (a valid URL) and sender_reminder must be present after the update. A list's channel cannot be changed after creation.
Sender address and visibility
The postal sender fields (sender_name, sender_addr1, sender_addr2, sender_city, sender_state, sender_zip, sender_country, sender_phone) and private are updatable, as they are on POST /lists, so the fields the v1 list_edit action wrote can all be written here.
The sender address may be updated in part: when a request carries any of the postal sender fields, the address shown in the footer of the list's campaigns is rebuilt from the list's stored values with the submitted values applied over them, so the fields the request leaves out keep their stored value. A field submitted as an empty string is removed from the address.
