When the user sees no results in their admin sidebar query,
we are adding two additional links:
* "Search site settings" - Navigates to the site settings page
with the filter prefilled in the search
* "Admin user list" - Navigates to the user list with the filter
prefilled in the username search
This will bridge the gap until we have a full admin-wide search.
Also make admin site setting search param refresh on filter changes
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Co-authored-by: Jarek Radosz <jradosz@gmail.com>