feat(nimbus): show metric details modal for metrics without results (#15688)

Because

* users cannot open the metric details modal when a metric has no
results
* metric descriptions can still be useful even without data

This commit

* makes the metric clickable even when metric data is unavailable and
shows metric description

Fixes #15668

<img width="1707" height="698" alt="Screenshot 2026-05-20 at 4 10 39 PM"
src="https://github.com/user-attachments/assets/9f479893-91b4-4e98-bc0f-b6feb696dbc2"
/>
<img width="1716" height="746" alt="Screenshot 2026-05-20 at 4 10 50 PM"
src="https://github.com/user-attachments/assets/74fa58f6-9f67-4135-9533-843c133ad2f1"
/>

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Co-authored-by: Rana Al-Khulaidi <ralkhulaidi@Ranas-MacBook-Pro.local>

Author: RJAK11