feat(tracemetrics): add visualize reset button (#122940)

This PR adds a reset button to the `visualize` row the same way
`groupBy` added in EXP-802. In short, anytime a chart/equation is added
or changed, the reset (trash) button will appear, allowing you to reset
said chart/equation. This was the case for 2 or more chart/equations,
but this PR added that behavior for the 1st equation if that is changed
from its default `count` value.

Before
<img width="347" height="296" alt="Screenshot 2026-08-27 at 3 10 50 PM"
src="https://github.com/user-attachments/assets/4c557da6-87bb-448c-8d12-b165970e1a72"
/>

After
<img width="361" height="268" alt="Screenshot 2026-08-27 at 3 11 22 PM"
src="https://github.com/user-attachments/assets/4c71af7b-518b-4ead-a0de-7f34892de2be"
/>

Addresses EXP-837