chore: remove unnecessary dependency to velodyne_monitor (tier4#19)

Signed-off-by: Ryohsuke Mitsudome <ryohsuke.mitsudome@tier4.jp>

Author: mitsudome-r

common_awsim_labs_sensor_launch/package.xml

@@ -10,7 +10,6 @@
   <buildtool_depend>ament_cmake_auto</buildtool_depend>
 
   <exec_depend>velodyne_driver</exec_depend>
-  <exec_depend>velodyne_monitor</exec_depend>
   <exec_depend>velodyne_pointcloud</exec_depend>
 
   <test_depend>ament_lint_auto</test_depend>