[AB-xxx] fixing user leave messages

changing structure of starboard post messages

abstracto-modules/logging/src/main/resources/default/listener/user_left/user_leave_embed.ftl

@@ -2,7 +2,7 @@
     "embeds": [
         {
             <#include "user_detail">
-            <#assign user><@user_detail user=user/></#assign>
+            <#assign userText><@user_detail user=user/></#assign>
             "description": "<@safe_include "user_left_text"/>",
             <#include "abstracto_color"/>
         }