Core/SmartAI: delay SMART_ACTION_FLEE_FOR_ASSIST if creature is rooted/stunned.

Prevents creatures from teleporting around when fleeing while stunned/rooted.

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

@@ -3373,6 +3373,16 @@ void SmartScript::UpdateTimer(SmartScriptHolder& e, uint32 const diff)
             }
         }
 
+        // Delay flee for assist event if stunned or rooted
+        if (e.GetActionType() == SMART_ACTION_FLEE_FOR_ASSIST)
+        {
+            if (me && me->HasUnitState(UNIT_STATE_ROOT | UNIT_STATE_STUNNED))
+            {
+                e.timer = 1;
+                return;
+            }
+        }
+
         e.active = true;//activate events with cooldown
         switch (e.GetEventType())//process ONLY timed events
         {