Fix apm_pluginlist.yaml and apm.launch

[eMrazSVK]

If these changes are not made, there are several errors when trying to launch apm.launch . ROS2 Foxy.

1. error:

[ERROR] [mavros_node-1]: process has died [pid 59547, exit code -6, cmd '/home/dcs_user/ros2_ws/install/mavros/lib/mavros/mavros_node --ros-args -r __ns:=/mavros --params-file /tmp/launch_params_u3s_gn73 --params-file /tmp/launch_params_l0ol9u7q --params-file /tmp/launch_params_9v2uyjt4 --params-file /tmp/launch_params_p_qmy_03 --params-file /tmp/launch_params_pslty43k --params-file /home/dcs_user/ros2_ws/install/mavros/share/mavros/launch/apm_pluginlists.yaml --params-file /home/dcs_user/ros2_ws/install/mavros/share/mavros/launch/apm_config.yaml'].

2. error:

ValueError: $(var log_output) is not a valid standard output config i.e. "screen", "log" or "both"

EDIT: add info

[vooon]

LGTM, Thanks!