VSA - adding drill-up link to VSD comparison page

What does this MR do and why?

Adds a new link from the VSA page to the Value Streams Dashboard for the selected group.

The URL for the dashboard is always determined by the selected group:

• When viewing project VSA, the link includes the project path as a query parameter
• When viewing group VSA, but with selected projects, the link includes the projects as a query parameter

Screenshots or screen recordings

Group VSA	Group VSA mobile	Project VSA	Project VSA mobile

How to set up and validate locally

1. Enable the group_analytics_dashboards_page feature flag

   Feature.enable(:group_analytics_dashboards_page)

2. Ensure you're on an ultimate plan
3. Visit VSA for any group
4. Visit VSA for any project
5. The link will appear under the "Key metrics" title

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #388286 (closed)