Remove script to break out of iframes

lms/templates/main.html

@@ -46,17 +46,6 @@ from branding import api as branding_api
       </title>
   </%block>
 
-  % if not allow_iframing:
-      <script type="text/javascript">
-        /* immediately break out of an iframe if coming from the marketing website */
-        (function(window) {
-          if (window.location !== window.top.location) {
-            window.top.location = window.location;
-          }
-        })(this);
-      </script>
-  % endif
-
   <script type="text/javascript" src="/jsi18n/"></script>
 
   <link rel="icon" type="image/x-icon" href="${static.url(microsite.get_value('favicon_path', settings.FAVICON_PATH))}" />