Host can't see private submissions toggle not available when no public submissions are available on leaderboard

When the host goes to the leaderboard, he is not able to see the private submissions at first. And if no public submissions are available, then it directly shows that no results are available. The toggle to include/exclude private submissions does not appear in this case. Therefore, if for a particular challenge all the submissions are private, then the host would see no submissions in the leaderboard, and nor would he get a toggle to include private submissions in his view.
Therefore, the toggle to include/exclude private submissions also be available if `leaderboard.length === 0`