Migrate tests to use new Handle API

[saikishor]

This changes the StateInterface and CommandInterfaces used inside the tests to use the new Handles API and to move away from the deprecated API, so it'll be easier to break the API of the Handle where it needed a variable reference parsed. This is the first step toward that direction

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.54%. Comparing base (225de17) to head (e7655aa).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2369      +/-   ##
==========================================
- Coverage   85.60%   85.54%   -0.06%     
==========================================
  Files         145      145              
  Lines       15720    15706      -14     
  Branches     1338     1338              
==========================================
- Hits        13457    13436      -21     
- Misses       1778     1784       +6     
- Partials      485      486       +1     

Flag	Coverage Δ
unittests	85.54% <100.00%> (-0.06%)	⬇️

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

Files with missing lines	Coverage Δ
...ned_filter_controller/test/test_chained_filter.cpp	98.33% <ø> (ø)
...ned_filter_controller/test/test_chained_filter.hpp	100.00% <ø> (ø)
...r_controller/test/test_multiple_chained_filter.cpp	98.11% <ø> (ø)
...r_controller/test/test_multiple_chained_filter.hpp	100.00% <ø> (ø)
...ive_controller/test/test_diff_drive_controller.cpp	95.09% <100.00%> (+0.02%)	⬆️
..._controllers/test/test_gpio_command_controller.cpp	97.67% <ø> (ø)
...r_broadcaster/test/test_gps_sensor_broadcaster.cpp	100.00% <ø> (ø)
..._broadcaster/test/test_joint_state_broadcaster.cpp	97.44% <100.00%> (-0.13%)	⬇️
pose_broadcaster/test/test_pose_broadcaster.hpp	88.88% <ø> (ø)
...broadcaster/test/test_range_sensor_broadcaster.cpp	95.23% <100.00%> (+0.18%)	⬆️
... and 1 more

... and 1 file with indirect coverage changes

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