Update illustrations

What does this MR do and why?

1. Replace jobs-empty-state, search-timeout-md and ondemand-scan-empty illustrations
2. Remove jobs-empty-state illustration — it's no longer used

Screenshots or screen recordings

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

Before	After

How to set up and validate locally

1. Go to /new-group/new-project/-/jobs

2. See illustration

3. Go to /new-group/new-project/-/on_demand_scans

4. See illustration

I don't know how to reproduce the search error correctly, but sometimes it happens 🤷

1. Go to /search
2. Try to overload the search to see the error, for example, "Your search timed out"
3. See illustration

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.

#424403 (closed)