Log an error if update() call returns ERROR

[christophfroehlich]

As we discussed in #1873: On humble we do not take any action if the update call of a controller returns ERROR. As we don't want to break the behavior on humble, I suggest adding at least a log output.

I'm just not sure if we should just print it once, throttled, or on every call.

Closes #1873

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 62.91%. Comparing base (5c5a171) to head (0430bd4).

Files with missing lines	Patch %	Lines
controller_manager/src/controller_manager.cpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           humble    #1969      +/-   ##
==========================================
- Coverage   62.92%   62.91%   -0.01%     
==========================================
  Files         109      109              
  Lines       12504    12505       +1     
  Branches     8481     8482       +1     
==========================================
  Hits         7868     7868              
- Misses        852      853       +1     
  Partials     3784     3784              

Flag	Coverage Δ
unittests	62.91% <0.00%> (-0.01%)	⬇️

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Files with missing lines	Coverage Δ
controller_manager/src/controller_manager.cpp	67.00% <0.00%> (-0.06%)	⬇️

[saikishor]

The problem with the _ONCE is it will print once for the first controller and will never print it again.

[saikishor]

@christophfroehlich like you. I'm also not sure which is the best option for this. Logging every time might spam a bit, and with throttle might miss some logs. Once might not be a good one here.