Add illustration to Value Stream Analytics empty state

What does this MR do and why?

Add illustration to Value Stream Analytics empty state

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Before	After

How to set up and validate locally

Visit /flightjs/Flight/-/value_stream_analytics?created_after=2023-03-25

#424397 (closed)

Closes #426001 (closed)