Navigator: Increase RAM size

src/modules/navigator/navigator_main.cpp

@@ -670,7 +670,7 @@ Navigator::start()
 	_navigator_task = px4_task_spawn_cmd("navigator",
 					     SCHED_DEFAULT,
 					     SCHED_PRIORITY_DEFAULT + 5,
-					     1600,
+					     1800,
 					     (px4_main_t)&Navigator::task_main_trampoline,
 					     nullptr);