Remove "Recent History" from sidebar on search results page

Created by: jjinnii

To better mirror the experience of sourcegrah.com, we should remove "Recent History" from the extension sidebar when a user is on a search results page. Currently, Recent History (Recent Repositories, Recent Files, Recent Searches) are only populated on the homepage of sourcegraph.com. Removing "Recent History" also helps to declutter the sidebar when utilizing filters for search results.

Current state:

Expected State: Designs