Prevent users from creating a pad when visiting a deleted profile (read-only mode)

www/common/sframe-protocol.js

@@ -227,4 +227,7 @@ define({
     // This is for sending data out of the iframe when we are in testing mode
     // The exact protocol is defined in common/test.js
     'EV_TESTDATA': true,
+
+    // Critical error outside the iframe during loading screen
+    'EV_LOADING_ERROR': true,
 });