fix: Changes email validation to match @LearningLocker. (Thanks @AndyHubert - #281)

src/transformer/utils/get_user.php

@@ -19,7 +19,8 @@ defined('MOODLE_INTERNAL') || die();
 
 function get_user(array $config, \stdClass $user) {
     $fullname = get_full_name($user);
-    $hasvalidemail = filter_var($user->email, FILTER_VALIDATE_EMAIL);
+    // The following email validation matches that in Learning Locker
+    $hasvalidemail = mb_ereg_match("[A-Z0-9\\.\\`\\'_%+-]+@[A-Z0-9.-]+\\.[A-Z]{1,63}$", $user->email, "i");
 
     if (array_key_exists('send_mbox', $config) && $config['send_mbox'] == true && $hasvalidemail) {
         return [