fix(mgb): update fastrun log level when not set timeout

GitOrigin-RevId: d33cfd543d5bb4d1da4fd114fc4ef54eff7bafbe

src/core/impl/system.cpp

@@ -488,7 +488,7 @@ class TimedFuncInvokerImpl final: public TimedFuncInvoker {
             return iter->second.direct_call(param);
 
         if (!m_fork_exec_impl) {
-            mgb_log_error("timeout is set, but no fork_exec_impl not given; "
+            mgb_log_warn("timeout is set, but no fork_exec_impl not given; "
                     "timeout would be ignored");
             return iter->second.direct_call(param);
         }