Remove conditional when rendering search tabs

** Why are these changes being introduced:

Currently, if the initial DOM rendering is done in a condition where
there are no search results, the UI doesn't not include tabs to change
to a different set of results - which prevents the user from potentially
finding results that were initially excluded.

** Relevant ticket(s):

* https://mitlibraries.atlassian.net/browse/use-172

** How does this address that need:

This removes a conditional in the view logic that skipped tabs if there
were no results - thus ensuring that tabs are always rendered.

** Document any side effects to this change:

Hopefully none - need to confirm this with GeoData.

Author: matt-bernhardt

app/views/search/_form.html.erb

@@ -31,6 +31,6 @@
     </aside>
 <% end %>
 
-<%= render partial: 'search/source_tabs' if @results.present? %>
+<%= render partial: 'search/source_tabs' %>
 
 <%= javascript_include_tag "search_form" %>