Fixed codestyle fix (mod-playerbots#1815)

Fix for this changes
<img width="1055" height="193" alt="obraz"
src="https://github.com/user-attachments/assets/a3d64f5b-80b0-4150-9760-0bcd4847f5d2"
/>

Author: kadeshar

src/GuildTaskMgr.cpp

@@ -1067,7 +1067,7 @@ void GuildTaskMgr::SendCompletionMessage(Player* player, std::string const verb)
 void GuildTaskMgr::CheckKillTaskInternal(Player* player, Unit* victim)
 {
     ObjectGuid::LowType owner = player->GetGUID().GetCounter();
-    if (victim->IsCreature())
+    if (!victim->IsCreature())
         return;
 
     Creature* creature = reinterpret_cast<Creature*>(victim);