Load SkiROS2 GUI from ROS 2 launch file

[matthias-mayr]

In eb2195f I disabled to load the GUI directly with arguments from the launch file with this block:

skiros2/skiros2/launch/skiros2.launch.py

Lines 56 to 59 in eb2195f

	gui = Node(package='rqt_gui',
	executable='rqt_gui',
	# arguments=["-s skiros2_gui.gui.Skiros"], # does not find the plugin. Not sure why - it appears in the list and can be selected with "ros2 run"
	output='screen')

For some reason it does not find it and then rqt does not startup at all.

Things that I checked:

• the plugin appears in the rqt list of plugins
• other plugins can not be loaded with "-s " as well
• the generated node string works in the terminal directly:
  /opt/ros/humble/lib/rqt_gui/rqt_gui -s skiros2_gui.gui.Skiros --ros-args

For now this just does not load the GUI directly. Once rqt is up, one can select it from the menu. When rqt is started again, it would also automatically show the SkiROS2 GUI again.

Unfortunately I could not find a launch file example on the internet that directly loads an rqt plugin.