Add ability to download chart CSV from metrics dashboard

What does this MR do?

Adds a Download CSV button to download all metrics data from dashboard.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Implements #60733 (closed)

Follow up issue: #64950 (closed)