check_the_controller_update_rate is flaky

[christophfroehlich]

I saw that several times now, mostly on humble

https://github.com/ros-controls/ros2_control_ci/actions/runs/12385126242/job/34570846255

     1 FAILED TEST
    -- run_test.py: return code 1
    -- run_test.py: inject classname prefix into gtest result file '/home/runner/work/ros2_control_ci/ros2_control_ci/.work/target_ws/build/controller_manager/test_results/controller_manager/test_controller_manager.gtest.xml'
    -- run_test.py: verify result file '/home/runner/work/ros2_control_ci/ros2_control_ci/.work/target_ws/build/controller_manager/test_results/controller_manager/test_controller_manager.gtest.xml'
  >>>
build/controller_manager/test_results/controller_manager/test_controller_manager.gtest.xml: 30 tests, 0 errors, 1 failure, 0 skipped
- controller_manager.per_controller_update_rate_check/TestControllerUpdateRates check_the_controller_update_rate/10
  <<< failure message
    /home/runner/work/ros2_control_ci/ros2_control_ci/.work/target_ws/src/ros-controls/ros2_control/controller_manager/test/test_controller_manager.cpp:736
    Value of: test_controller->update_period_.seconds()
    Expected: (is > 0.011) and (is < 0.0216667)
      Actual: 0.022103 (of type double)
    update_counter: 117 desired controller period: 0.011111111111111112 actual controller period: 0.022103009999999999
    /home/runner/work/ros2_control_ci/ros2_control_ci/.work/target_ws/src/ros-controls/ros2_control/controller_manager/test/test_controller_manager.cpp:736
    Value of: test_controller->update_period_.seconds()
    Expected: (is > 0.011) and (is < 0.0216667)
      Actual: 0.022103 (of type double)
    update_counter: 118 desired controller period: 0.011111111111111112 actual controller period: 0.022103009999999999
  >>>

[christophfroehlich]

ros-controls/ros2_control_ci#217