Bench: Update CheckBroadcast Cron defaults

When we create a broadcast, a checkbroadcast cron is automatically created to poll the oceanTV service. The default for the cron is now set to https://tv.cloudblue.org. However, the cron lit element (cmd/oceanbench/ts/cron-settings.ts) still uses the old value of oceantv.appspot.tv.

Whilst this still it works, it means that the cron element does not detect that the production cron has been selected, and displays "other" indicating that a non-standard endpoint is being used.