Add a short sleep after powering on the robot

It seems like this could lead to flakiness in CI otherwise.

Author: urfeex

examples/dashboard_example.cpp

@@ -36,6 +36,7 @@
 #include <iostream>
 #include <memory>
 #include <thread>
+#include <unistd.h>
 
 using namespace urcl;
 
@@ -96,6 +97,8 @@ int main(int argc, char* argv[])
     return 1;
   }
 
+  sleep(1);
+
   // Play loaded program
   if (!my_dashboard->commandPlay())
   {