Per T310852, we want to know a user's user groups when they take actions logged by MobileWebUIActionsTracking. The primary use case is to know which users are clicking the 'switch to desktop' button from their mobile devices, so that we understand the situations in which users find the mobile website lacking in functionality.
In T310852 we added the 'switch to desktop' tracking, and discovered that user groups are not presently tracked. The scope of this ticket is to add that data to the tracking schema.
