Bits leaderboard should error if no started_at but period

[BarryCarlyon]

Brief description

The Bits Leaderboard says that if you use a period of not all you need to specify a started_at if you don't specify a started_at then it doesn't error it just returns no data.

How to reproduce

Call https://api.twitch.tv/helix/bits/leaderboard?count=2&period=week and get no data

Call https://api.twitch.tv/helix/bits/leaderboard?started_at=2021-01-29T00:00:00Z&period=week&count=2 and get data.

The former should error indicating the missing started_at

Expected behavior

If you specify a period and no started_at return an error

Additional context or questions

https://discuss.dev.twitch.tv/t/issue-with-curl-query-for-bits-leaderboard/30201

[scott-a-white]

Thanks Barry for the feedback. Going to close this since it looks like the code has been fixed and the doc update will go out in this week's build.