Core/Unit: Guardians no longer enter combat before reaching the target (#19816)

(cherry picked from commit a891eb364e941a5146fba4af16e1ecf65cdd9239)

src/server/game/Entities/Unit/Unit.cpp

@@ -5482,7 +5482,7 @@ bool Unit::Attack(Unit* victim, bool meleeAttack)
     //if (GetTypeId() == TYPEID_UNIT)
     //    ToCreature()->SetCombatStartPosition(GetPositionX(), GetPositionY(), GetPositionZ());
 
-    if (creature && !IsPet())
+    if (creature && !IsControlledByPlayer())
     {
         EngageWithTarget(victim); // ensure that anything we're attacking has threat