PLEASE NOTE THAT THIS DIFF AND SUBSEQUENT DIFFS IN THIS STACK WILL NOT BE LANDED UNTIL MORE OF THE REDESIGN IS READY SINCE THIS WILL CAUSE REGRESSIONS IN PROD
In order to use the add users list for both add friends + add members, we need to make this component completely generic. Right now there is a lot of business logic for searching for any user to add as a friend that needs to be factored out.
This diff introduces a new generic BaseAddUserInfo type that both adding friends + adding members modals can use and lifts the rest of the business logic for adding friends out of AddUsersList and into AddUsersListModalContent
Depends on D10937