When we have an approval flow, `pending-approval` will be the state a
broadcast is in between being a draft and broadcasting.
This means it is the earliest stage at which a broadcast can appear on
the dashboard, so this commit adds a new section at the top of the
dashboard to display these broadcasts (since the dashboard is in a
reverse chronological order).
Rather than displaying the scheduled time, the extra information shown
is the person who drafted the broadcast, since I reckon you’ll be coming
to this page because they’ve asked you to approve their broadcast.