Add analytics dashboard empty state

What does this MR do and why?

This MR adds an empty state to the analytics dashboard page when no dashboard matching the URL path is found for #379106 (closed).

Note: I'm using the empty state design from Dashboards listing - improving upon the new pro... (#391495).

Note: this feature is hidden behind a default off feature flag.

Screenshots or screen recordings

/product_analytics	/analytics

How to set up and validate locally

To test the product analytics dashboard items are shown, you will need to follow the instructions at https://gitlab.com/gitlab-org/gitlab/-/snippets/2474959 to enable Product Analytics on your GDK.

Then visit the projects shared dashboards listing at:

• http://gdk.test:3000/gitlab-org/gitlab-test/-/analytics/dashboards/asdasddads
• http://gdk.test:3000/gitlab-org/gitlab-test/-/product_analytics/dashboards/asdasddads

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 #379106 (closed)