Support for gpu_ray for "base_laser" and "base_laser2" sensors in cer_no_collisions/cer.sdf

[morpheus1820]

Laser sensor type "ray" is unable to detect animated actors, which would require using "gpu_ray", which should also be faster.
However, when trying to change sensor type "ray" to "gpu_ray", the simulation does not start.

It would be useful to be able to use the standard gazebo laser plugin (libgazebo_ros_ray_sensor.so in ros2) for the two lasers instead of libgazebo_yarp_lasersensor.so (or understand why libgazebo_yarp_lasersensor does not currently work with gpu_ray).