[CM] Use explicit constants in controller tests. (backport #1356)

[mergify]

This is an automatic backport of pull request #1356 done by Mergify.

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[codecov]

Codecov Report

Attention: 27 lines in your changes are missing coverage. Please review.

Comparison is base (06f5876) 31.03% compared to head (ebbca88) 31.03%.
Report is 1 commits behind head on humble.

Additional details and impacted files

@@           Coverage Diff           @@
##           humble    #1359   +/-   ##
=======================================
  Coverage   31.03%   31.03%           
=======================================
  Files          95       95           
  Lines       10729    10729           
  Branches     7421     7421           
=======================================
  Hits         3330     3330           
  Misses        723      723           
  Partials     6676     6676           

Flag	Coverage Δ
unittests	31.03% <0.00%> (ø)

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Files	Coverage Δ
controller_manager/test/test_load_controller.cpp	26.43% <0.00%> (ø)