MDL-69644 tool_dataprivacy: fix focus outline of contact DPO link.

The link class attribute is a leftover from 7258bf0b, which was mostly
removed in 3b2f691f. It no longer serves a purpose and interferes with
the element focus outline.

admin/tool/dataprivacy/classes/output/renderer.php

@@ -63,7 +63,6 @@ class renderer extends plugin_renderer_base {
         $params = [
             'data-action' => 'contactdpo',
             'data-replytoemail' => $replytoemail,
-            'class' => 'contactdpo'
         ];
         return html_writer::link('#', get_string('contactdataprotectionofficer', 'tool_dataprivacy'), $params);
     }