Add related traces widget to metrics details view

What does this MR do and why?

Add related traces widget to metrics details view for Create RelatedTraces widget (gitlab-org/opstrace/opstrace#2943 - closed).

Feature timeline:

1. Extract data from metrics charts to feed into t... (!164853 - merged)
2. Clicking on a metrics chart data point now reveals related traces. 👈 YOU ARE HERE
3. Improve metrics charts symbols (#483071 - moved).

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Recording

Screen_Recording_2024-09-09_at_12.08.37

Default behaviour

No visual change except for line chart margin update.

Click to expand

Before	After

Clicked on data point

Click to expand

Before	After

How to set up and validate locally

1. You need a GitLab Ultimate license.
2. Enable the :observability_features feature flag enabled.
3. Apply patch to load local mocks git apply < <(curl -s https://gitlab.com/gitlab-org/opstrace/opstrace/-/snippets/3744171/raw/main/mock.patch)
4. View the metrics list page at Projects > Monitor > Metrics.
   • View the metrics details page with line chart by selecting a "Sum" metric.
   • View the metrics details page with histogram by selecting a "Histogram" metric.
5. Click on data points to view the new related traces widget.