Fix #583: `activated` vs `is_activated`

Thank you to @chiragpipariya for his initial fix in #586.

Modules/User/Repositories/Sentinel/SentinelUserRepository.php

@@ -260,7 +260,7 @@ class SentinelUserRepository implements UserRepository
      */
     private function checkForManualActivation($user, array &$data)
     {
-        if (Activation::completed($user) && !$data['activated']) {
+        if (Activation::completed($user) && !$data['is_activated']) {
             return Activation::remove($user);
         }