feat(nimbus): add labels to metric areas

[moibra05]

Because

• The old results page had useful labels next to each metric listing them as either: guardrails, primary, or secondary
• These labels were missing from the new designs and were not included on the page

This commit

• Adds theses labels next to the metric area titles

Fixes #14905

[moibra05]

[jaredlockhart]

Ya looks good. Couple thoughts on wording for the tooltips but nothing major. Looks good thnx @moibra05 🙏