Use govuk_link_to helper for helpdesk link

app/views/layouts/_footer.html.erb

@@ -5,7 +5,8 @@
 
       <h3 class="govuk-heading-s govuk-!-margin-bottom-1">Online helpdesk</h3>
       <p class="govuk-body govuk-!-font-size-16">
-        <a class="govuk-link govuk-footer__link" href="https://digital.dclg.gov.uk/jira/servicedesk/customer/portal/4/group/21" rel="noreferrer noopener" target="_blank">CORE helpdesk (opens in a new tab)</a></p>
+        <%= govuk_link_to("CORE helpdesk (opens in a new tab)", "https://digital.dclg.gov.uk/jira/servicedesk/customer/portal/4/group/21", class: "govuk-footer__link", rel: "noreferrer noopener", target: "_blank") %>
+      </p>
 
       <h3 class="govuk-heading-s govuk-!-margin-bottom-1">Telephone</h3>
       <ul class="govuk-list govuk-!-font-size-16">