test_trajectory_following: disable trajectory visualization to avoid Rviz update delay

Description

Disable trajectory visualization in test_trajectory_following package as a temporal fix for this issue #547 (closed)

Note: the trajectory is visible with the bounding box (MarkerArray).

Checklist

Please launch the following command, and check that the checkbox of the trajectory plugin is disabled on Rviz as the picture below.

ros2 launch test_trajectory_following trajectory_recording.launch.py