Fix comment replies being duplicated during S/R

Turns out it was quite simple: the reply GUIDs weren't being tracked by
PHP and sent to the Javascript frontend, so when the frontend created a
new reply and updated the entire list of replies, it sent a list with no
GUIDs in it. Simply keeping track of the reply GUIDs in PHP is enough to
get rid of this bug.


Former-commit-id: 9213336

src/Api/Model/Languageforge/Lexicon/LexCommentReply.php

@@ -23,6 +23,9 @@ public function __construct($content = '')
     /** @var string */
     public $id;
 
+    /** @var string */
+    public $guid;
+
     /** @var boolean */
     public $isDeleted;
 }