Code Insights: Add aggregation full UI mode mock on the search result page

Created by: vovakulikov

RFC Figma Desings

In this issue, we should add a mock UI for the full aggregation mode on the search result page. It should be dependent on https://github.com/sourcegraph/sourcegraph/pull/40138.

/cc @joelkw @felixfbecker @vovakulikov @unclejustin