I guess the changes that involved `MultiplayerTestScene` having a test
user lookup cache caused this test case to false-pass silently.
Added an explicit assert which ensures the added user indeed has a null
`User` value.
The previous version tried to keep both normal multiplayer and team
multiplayer results as one screen, but didn't check that team-specific
components aren't null in `LoadComplete()`.
To decrease number of conditional, split off the team results screen to
a separate implementation, and choose one or the other at push time in
`MultiplayerPlayer`, depending on team count.
Hiding just one user never makes sense, so this will now always show up
to the required circle count until two users are required to be hidden.
This will make the listing more consistent with the width requirement
spec.