Make sim pblog shutdown gracefully

[andermi]

This was bugging me ;-p and isn't actually an error...

Before:

[gazebo-1] [INFO] [1758566944.225722422] [rclcpp]: signal_handler(signum=2)
[INFO] [gazebo-1]: process has finished cleanly [pid 966942]
[INFO] [launch]: process[gazebo-1] was required: shutting down launched system
[INFO] [sim_pblog-3]: sending signal 'SIGINT' to process[sim_pblog-3]
[INFO] [parameter_bridge-2]: sending signal 'SIGINT' to process[parameter_bridge-2]
[sim_pblog-3] Traceback (most recent call last):
[sim_pblog-3]   File "/home/anderson/wec/igngzb/openrobotics/workspace/install/sim_pblog/lib/sim_pblog/sim_pblog", line 33, in <module>
[sim_pblog-3]     sys.exit(load_entry_point('sim-pblog==0.0.0', 'console_scripts', 'sim_pblog')())
[sim_pblog-3]              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[parameter_bridge-2] [INFO] [1758566944.654985153] [rclcpp]: signal_handler(signum=2)
[sim_pblog-3]   File "/home/anderson/wec/igngzb/openrobotics/workspace/install/sim_pblog/lib/python3.12/site-packages/sim_pblog/sim_pblog.py", line 409, in main
[sim_pblog-3]     rclpy.spin_once(pblog)
[sim_pblog-3]   File "/opt/ros/jazzy/lib/python3.12/site-packages/rclpy/__init__.py", line 226, in spin_once
[sim_pblog-3]     executor.spin_once(timeout_sec=timeout_sec)
[sim_pblog-3]   File "/opt/ros/jazzy/lib/python3.12/site-packages/rclpy/executors.py", line 839, in spin_once
[sim_pblog-3]     self._spin_once_impl(timeout_sec)
[sim_pblog-3]   File "/opt/ros/jazzy/lib/python3.12/site-packages/rclpy/executors.py", line 823, in _spin_once_impl
[sim_pblog-3]     handler, entity, node = self.wait_for_ready_callbacks(
[sim_pblog-3]                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[sim_pblog-3]   File "/opt/ros/jazzy/lib/python3.12/site-packages/rclpy/executors.py", line 793, in wait_for_ready_callbacks
[sim_pblog-3]     return next(self._cb_iter)
[sim_pblog-3]            ^^^^^^^^^^^^^^^^^^^
[sim_pblog-3]   File "/opt/ros/jazzy/lib/python3.12/site-packages/rclpy/executors.py", line 697, in _wait_for_ready_callbacks
[sim_pblog-3]     wait_set.wait(timeout_nsec)
[sim_pblog-3] KeyboardInterrupt
[INFO] [parameter_bridge-2]: process has finished cleanly [pid 966943]
[ERROR] [sim_pblog-3]: process has died [pid 966944, exit code -2, cmd '/home/anderson/wec/igngzb/openrobotics/workspace/install/sim_pblog/lib/sim_pblog/sim_pblog --loghome /home/anderson/.pblogs --logdir --ros-args -r __node:=sim_pblog --params-file /home/anderson/wec/igngzb/openrobotics/workspace/install/sim_pblog/share/sim_pblog/config/sim_pblog.yaml'].

After:

[gazebo-1] [INFO] [1758568219.200409452] [rclcpp]: signal_handler(signum=2)
[INFO] [gazebo-1]: process has finished cleanly [pid 973198]
[INFO] [launch]: process[gazebo-1] was required: shutting down launched system
[INFO] [sim_pblog-3]: sending signal 'SIGINT' to process[sim_pblog-3]
[INFO] [parameter_bridge-2]: sending signal 'SIGINT' to process[parameter_bridge-2]
[parameter_bridge-2] [INFO] [1758568219.529937738] [rclcpp]: signal_handler(signum=2)
[INFO] [parameter_bridge-2]: process has finished cleanly [pid 973199]
[INFO] [sim_pblog-3]: process has finished cleanly [pid 973201]