Exposing publish button only to staff users

LEARNER-2473

course_discovery/apps/publisher/templates/publisher/course_run_detail/course_run_detail.html

@@ -49,7 +49,9 @@
                 </h2>
             </div>
 
+        {% if request.user.is_staff %}
           <button class="btn btn-primary" onclick="publish('{% url 'publisher:api:v1:course_run-publish' pk=object.pk %}');">{% trans "Publish" %}</button>
+        {% endif %}
 
           <div class="alert hidden" role="alert" aria-labelledby="alertTitle" tabindex="-1" id="alertContainer" style="margin:15px 0;">
             <span class="icon alert-icon fa" aria-hidden="true"></span>