Remove no-branch from release dashboard

[hugovk]

Does anyone use the no-branch section of the release dashboard?

If not, let's remove it. This would save fetching data for 142 of the 1,074 builders listed on the page, about 13%.

A cached page takes about 2s:

❯ curl -s -o /dev/null -w "ttfb: %{time_starttransfer}s  total: %{time_total}s\n" \
    "https://buildbot.python.org/plugins/wsgi_dashboards/release_status/index.html"
ttfb: 0.637072s  total: 2.030991s

Forcing a refresh:

❯ curl -s -o /dev/null -w "ttfb: %{time_starttransfer}s  total: %{time_total}s\n" \
    "https://buildbot.python.org/plugins/wsgi_dashboards/release_status/index.html?refresh=1"

ttfb: 25.549996s  total: 25.550114s

ttfb is time to first byte, and tells us when the page has already finished querying all the data it needs, so this is roughly about how long it takes to run on the server.

Dropping no-branch would bring that to about 22s, and also save about 0.9 MB of the 13.2 MB HTML page.

The cron to refresh this page is every 5 mins so it's 12 times per hour:

https://github.com/python/psf-salt/blob/05305dee04372ad00c4dd66fca14ab13e35754f3/salt/buildbot/init.sls#L99-L103