Normalize fulfillment links

Why these changes are being introduced:

Fulfillment link logic exists in three separate
places. This is not necessary, as UXWS would like
the link text to always be 'View full record.'

Relevant ticket(s):

- [USE-252](https://mitlibraries.atlassian.net/browse/USE-252)

How this addresses that need:

This simplifies fulfillment link logic and
normalizes the text as requested.

Side effects of this change:

The nested conditional logic in the Primo result
partial is starting to get some code smell.
I find it unlikely that we'll want to render all
of the links long-term, though, so I think we
can accept this for now with the understanding
that it can probably be simplified later.

Author: jazairi

app/helpers/search_helper.rb

@@ -41,12 +41,6 @@ def link_to_tab(target, label = nil)
     end
   end
 
-  def view_online(result)
-    return unless result[:source_link].present?
-
-    link_to 'View online', result[:source_link], class: 'button button-primary'
-  end
-
   def view_record(record_id)
     link_to 'View full record', record_path(id: record_id), class: 'button button-primary'
   end

app/views/search/_result.html.erb

@@ -55,7 +55,7 @@
     </div>
 
     <div class="result-get">
-      <%= view_online(result) %>
+      <%= view_record(result) %>
     </div>
   </div>
 </li>

app/views/search/_result_primo.html.erb

@@ -60,7 +60,11 @@
     <div class="result-get">
       <% if result[:links].present? %>
         <% result[:links].each do |link| %>
-          <%= link_to link['kind'].titleize, link['url'], class: 'button' %>
+          <% if link['kind'].downcase == 'full record' %>
+            <%= view_record(link) %>
+          <% else %>
+            <%= link_to link['kind'].titleize, link['url'], class: 'button' %>
+          <% end %>
         <% end %>
       <% end %>
       <% if Libkey.enabled? && result[:doi].present? %>

test/helpers/search_helper_test.rb

@@ -26,17 +26,6 @@ class SearchHelperTest < ActionView::TestCase
                   { 'matchedField' => 'citation', 'matchedPhrases' => 'Datascientist, Jane' }], trim_highlights(result)
   end
 
-  test 'renders view_online link if source_link is present' do
-    result = { title: 'A record', source_link: 'https://example.org' }
-    assert_equal '<a class="button button-primary" href="https://example.org">View online</a>',
-                 view_online(result)
-  end
-
-  test 'does not render view_online link if source_link is absent' do
-    result = { title: 'A record' }
-    assert_nil view_online(result)
-  end
-
   test 'parse_geo_dates returns issued over coverage' do
     dates = [{ 'kind' => 'Coverage', 'value' => '2009-01-01' },
              { 'kind' => 'Issued', 'value' => '2011' }]