WIP: Resolve "Tooltip for new ECharts metrics chart"

What does this MR do?

Uses latest GitLab UI, which supports custom tooltip as a result of changes in gitlab-ui!136 (merged)

What are the relevant issue numbers?

Closes #54978 (closed)

Does this MR meet the acceptance criteria?

• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Security reports checked/validated by reviewer