mavlink, commander: Get back close to original stack sizes. Although tests came clean, we do not want to take any chances

src/modules/mavlink/mavlink_main.cpp

@@ -2193,7 +2193,7 @@ Mavlink::start(int argc, char *argv[])
 	task_spawn_cmd(buf,
 		       SCHED_DEFAULT,
 		       SCHED_PRIORITY_DEFAULT,
-		       1800,
+		       2000,
 		       (main_t)&Mavlink::start_helper,
 		       (const char **)argv);