[CM] Make error message after trying to active controller more informative.

[destogl]

No description provided.

[codecov-commenter]

Codecov Report

Merging #1066 (f74ead1) into master (925f5f3) will decrease coverage by 2.26%.
The diff coverage is 35.06%.

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@@            Coverage Diff             @@
##           master    #1066      +/-   ##
==========================================
- Coverage   34.61%   32.36%   -2.26%     
==========================================
  Files          52       94      +42     
  Lines        2981     9837    +6856     
  Branches     1855     6628    +4773     
==========================================
+ Hits         1032     3184    +2152     
- Misses        310      778     +468     
- Partials     1639     5875    +4236     

Flag	Coverage Δ
unittests	32.36% <35.06%> (-2.26%)	⬇️

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

Impacted Files	Coverage Δ
controller_manager/src/controller_manager.cpp	37.83% <ø> (-1.88%)	⬇️
controller_manager/src/ros2_control_node.cpp	0.00% <0.00%> (ø)
..._interface/include/hardware_interface/actuator.hpp	100.00% <ø> (ø)
...ce/include/hardware_interface/async_components.hpp	0.00% <0.00%> (ø)
...re_interface/include/hardware_interface/sensor.hpp	100.00% <ø> (ø)
...re_interface/include/hardware_interface/system.hpp	100.00% <ø> (ø)
hardware_interface/src/resource_manager.cpp	47.68% <ø> (-5.94%)	⬇️
hardware_interface/src/sensor.cpp	50.52% <ø> (ø)
hardware_interface/src/system.cpp	55.45% <ø> (ø)
...rface/test/mock_components/test_generic_system.cpp	9.42% <ø> (ø)
... and 71 more

... and 19 files with indirect coverage changes

[bmagyar]

Before/after?;)