Don't use implicit orders for conditional order waiting loops

Fixes vehicles never leaving when the only order is an implicit order
(because vehicles were released with no orders)

src/vehicle.cpp

@@ -3519,6 +3519,9 @@ static bool ShouldVehicleContinueWaiting(Vehicle *v)
 	/* Rate-limit re-checking of conditional order loop */
 	if (HasBit(v->vehicle_flags, VF_COND_ORDER_WAIT) && v->tick_counter % 32 != 0) return true;
 
+	/* Don't use implicit orders for waiting loops */
+	if (v->cur_implicit_order_index < v->GetNumOrders() && v->GetOrder(v->cur_implicit_order_index)->IsType(OT_IMPLICIT)) return false;
+
 	/* If conditional orders lead back to this order, just keep waiting without leaving the order */
 	bool loop = AdvanceOrderIndexDeferred(v, v->cur_implicit_order_index) == v->cur_implicit_order_index;
 	FlushAdvanceOrderIndexDeferred(v, loop);