The performance page expects all live services to have an organisation.
This should be true on production, but it isn’t always the case in
other environments.
When the organisation name is `None`, the frontend can’t sort the list
of organisations alphabetically and so raises an exception.
This uses the existing endpoint so it matches what’s on the homepage.
It will be more up-to-date than the list of services, but no-one’s going
to be adding things up to check they match exactly.
This matches the existing performance platform page, and I think is a
bit easier to read for high-level numbers where you don’t need to see
that they’re changing second-by-second.
