The "Task Completion Time Without Backpressure" metrics chart is broken.

I think it's because #57788 renamed task_completion_time_without_backpressure without updating the associated code in data_dashboard_panels.py:

What you need to do:

• Update the Grafana panel definition to use the correct name in the expr
• Run a simple Ray Data job and ensure the panel works correctly.
  • You'll need to setup Grafana and Prometheus to do this. Anecdotally, this can be difficult to set up for the first time. See https://docs.ray.io/en/latest/cluster/metrics.html for instructions.