MDL-64591 User tours: don't show during redirects & other bad times

admin/tool/usertours/classes/helper.php

@@ -497,6 +497,12 @@ class helper {
             return;
         }
 
+        if (in_array($PAGE->pagelayout, ['maintenance', 'print', 'redirect'])) {
+            // Do not try to show user tours inside iframe, in maintenance mode,
+            // when printing, or during redirects.
+            return;
+        }
+
         if (self::$bootstrapped) {
             return;
         }