We need to update the announcements endpoint to have the new article list for the experiment round of the exposure survey.
We also want to add a new field that will contain a 0 - 100 percentage value to represent which percentage of users would fall into the experiment bucket. This will give us the ability to configure this value server-side, should we want to traffic control things based on survey response rate and/or the server load.
We should also increase the version number of the survey announcement both server-side and client-side, AND we should update the google survey doc link to this (note we are capturing a couple of new fields): https://phabricator.wikimedia.org/T264057#6569804
Article list: https://phabricator.wikimedia.org/T267149 (any tickets that refer to other article lists should be updated to this one)