Use smart pointer of ctrl in GpsSensor and GpioCommandController tests

[jsantoso91]

Summary:
I am updating the tests to use smart pointers for the gps broadcaster and gpio controller. This is similar to other tests e.g. test_pose_broadcaster.cpp
This to remove warning LifecycleNode is not shut down during test as shown in test log https://github.com/ros-controls/ros2_controllers/actions/runs/14608595520/job/40982298949. Issue is captured in #1656

Qualification
$ pre-commit install
$ colcon build --packages-select gpio_controllers gps_sensor_broadcaster
$ colcon test --packages-select gpio_controllers gps_sensor_broadcaster --event-handlers console_direct+
See that the warnings are no longer present

I am relatively new to ROS/2 and ros_control ecosystems, let me know if I am missing anything, thanks!

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[codecov]

Codecov Report

Attention: Patch coverage is 98.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 84.79%. Comparing base (8c649a3) to head (5ab8b2e).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
..._controllers/test/test_gpio_command_controller.cpp	98.18%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1658      +/-   ##
==========================================
+ Coverage   84.77%   84.79%   +0.02%     
==========================================
  Files         127      127              
  Lines       12096    12114      +18     
  Branches     1036     1036              
==========================================
+ Hits        10254    10272      +18     
  Misses       1503     1503              
  Partials      339      339              

Flag	Coverage Δ
unittests	84.79% <98.66%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...r_broadcaster/test/test_gps_sensor_broadcaster.cpp	100.00% <100.00%> (ø)
..._controllers/test/test_gpio_command_controller.cpp	99.00% <98.18%> (+0.03%)	⬆️

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[christophfroehlich]

Thanks, this LGTM