Add `group_analytics_dashboard_dynamic_vsd` feature flag

What does this MR do and why?

This MR adds the group_analytics_dashboard_dynamic_vsd feature flag to allow us to toggle between the legacy hard-coded VSD page and the VSD page rendered as a shared analytics dashboard. This feature flag also depends on the existing group_analytics_dashboards feature flag.

This MR:

• Fixes the duplicate links to Value streams dashboard in the group level dashboards listing related to #429816 (closed)
• Allows us to toggle between the built in VSD and the new shared analytics dashboard VSD

Background

The two feature flags can be used to render a relevant VSD page:

• group_analytics_dashboards=false: always link to the hard-coded VSD page (existing behaviour so no change)
• group_analytics_dashboards=true + group_analytics_dashboard_dynamic_vsd=false: display the dashboard listing with a link to the hard coded VSD
• group_analytics_dashboards=true + group_analytics_dashboard_dynamic_vsd=true: display the dashboard listing with a link to the shared analytics dashboard VSD

This MR removes some of the temporary changes made in Extend AnalyticsDashboards to render group leve... (!132839 - merged), with the addition of the new feature flag we can properly separate the legacy VSD from the shared analytics dashboards VSD.

Known issues

• 500 error when using a custom YAML config - #430320 (closed)

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After - feature flag disabled	After - feature flag enabled
Screen_Recording_2023-11-20_at_4.24.32_pm	Screen_Recording_2023-11-17_at_5.11.32_pm	Screen_Recording_2023-11-17_at_5.13.27_pm

How to set up and validate locally

Enable the :group_analytics_dashboards feature flag

Feature.enable(:group_analytics_dashboards)

1. Create a group
2. Seed DORA metrics data for the selected project
3. Create a value stream for the project with seeded data
4. From the left sidebar, click the Analyze > Application analytics link (Not Analytics dashboards)
5. The group dashboard list should appear, select Value Stream Dashboard (should be the only option)
6. You will see the built in VSD page

Enable the :group_analytics_dashboard_dynamic_vsd feature flag

Feature.enable(:group_analytics_dashboard_dynamic_vsd)

1. From the left sidebar, click the Analyze > Application analytics link (Not Analytics dashboards)
2. The group dashboard list should appear, select Value Stream Dashboard (should be the only option)
3. You will see the shared analytics VSD page

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 #429816 (closed)

Related to #432185