Show expired task state totals in sidebar

[MetRonnie]

It makes sense to show expired tasks in the sidebar, right?

The question is:

• Add another badge like we have for retrying and held tasks?
• Include the total in the failed or submit-failed badge?

Note

Expired tasks are already included in the Cylc 8.6.2 stateTotals field in the schema, but not the latestStateTotals field apparently

[MetRonnie]

A grep suggests we're not currently using clock-expire operationally at the Met Office, but I think it could be useful going forward to expire:

• workflow-state triggered tasks for better visibility to operators when something is running late
• PBS reservation create tasks to avoid unnecessary effort during disaster recovery (but these wouldn't show in the sidebar as they would not be in n=0 due to expiry being handled in the graph)