Use location instead of campaign listener URL

The campaign listener URL can be anything (for instance an URL shortener), but when performing an admin function, it should refer to the admin URL itself.

static/js/src/app/campaign_results.js

@@ -933,7 +933,7 @@ function report_mail(rid, cid) {
     }).then(function (result) {
         if (result.value){
             api.campaignId.get(cid).success((function(c) {
-                report_url = new URL(c.url)
+                report_url = new URL(`${location.protocol}//${location.host}`)
                 report_url.pathname = '/report'
                 report_url.search = "?rid=" + rid
                 $.ajax({