test: Improve samples test scrolling and sorting interactions

Enhance system test for samples table by adding explicit scrolling to last column and refactoring sorting assertions within table header context

test/system/groups/samples_test.rb

@@ -487,15 +487,23 @@ def retrieve_puids
       within('table thead tr') do
         assert_selector 'th', count: 9
       end
+      # Scroll to the last column
+      within 'div.overflow-auto.scrollbar' do |div|
+        div.scroll_to div.find('table thead th:nth-child(9)')
+      end
 
-      click_on 'metadatafield1'
-      assert_selector 'table thead th:nth-child(7) svg.icon-arrow_up'
+      within('table thead') do
+        click_on 'metadatafield1'
+        assert_selector 'th:nth-child(7) svg.icon-arrow_up'
+      end
 
       assert_selector 'tbody tr:first-child th', text: @sample30.puid
       assert_selector 'tbody tr:first-child td:nth-child(2)', text: @sample30.name
 
-      click_on 'metadatafield2'
-      assert_selector 'table thead th:nth-child(8) svg.icon-arrow_up'
+      within('table thead') do
+        click_link 'metadatafield2'
+        assert_selector 'th:nth-child(8) svg.icon-arrow_up'
+      end
 
       assert_selector 'tbody tr:first-child th', text: @sample30.puid
       assert_selector 'tbody tr:first-child td:nth-child(2)', text: @sample30.name