Broadcasts created via the API [1] and the Admin app [2] should
both now have this field set. It's also more informative to show
this, and broadcasts created via the API don't have IDs anyway.
There's a small risk that an old broadcast that gets approved won't
have this data, but it's for information only and we intend to
backfill all old broadcasts in the near future.
[1]: 023a06d5fb
[2]: 7dbe3afa19