Metrics Dashboard Cleanup

Summary

These changes were suggested by Reuben during review of !15709 (merged).

!15709 (comment 216882270)

!15709 (comment 216882269)

!15709 (comment 216882268)

!15709 (comment 216882266)

!15709 (comment 216882265)

Improvements

Risks

Involved components

Optional: Intended side effects

Optional: Missing test coverage