After we default enabled the `group_analytics_dashboard_dynamic_vsd` feature flag we should ensure we cleanup / remove the feature flag and related code. We should now make sure we: - [x] [Remove the feature flag + Update related tests to remove their relevant test cases](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/151845) - [x] [Remove old code](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/152320) - [x] Remove references to the feature flag in docs - [x] Remove [legacy schema docs](https://docs.gitlab.com/ee/user/analytics/value_streams_dashboard.html#using-yaml-configuration) This will also be a good opportunity to revisit our documentation now that we have removed all the legacy configuration information.mo