Core/SmatAI: correct MoveInLineOfSight

mistake introduced in 15f2706aca that was masqueraded by other checks in combat start, till recent related commits

src/server/game/AI/SmartScripts/SmartAI.cpp

@@ -524,7 +524,7 @@ void SmartAI::MoveInLineOfSight(Unit* who)
     if (!IsAIControlled())
         return;
 
-    if (AssistPlayerInCombatAgainst(who))
+    if (HasEscortState(SMART_ESCORT_ESCORTING) && AssistPlayerInCombatAgainst(who))
         return;
 
     CreatureAI::MoveInLineOfSight(who);