Remove empty on_shutdown() callbacks (backport #1477)

[mergify]

Address #1474

---

This is an automatic backport of pull request #1477 done by Mergify.

[mergify]

Cherry-pick of abf3172 has failed:

On branch mergify/bp/humble/pr-1477
Your branch is up to date with 'origin/humble'.

You are currently cherry-picking commit abf3172.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   diff_drive_controller/src/diff_drive_controller.cpp
	modified:   joint_trajectory_controller/src/joint_trajectory_controller.cpp
	modified:   tricycle_controller/src/tricycle_controller.cpp

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   diff_drive_controller/include/diff_drive_controller/diff_drive_controller.hpp
	both modified:   joint_trajectory_controller/include/joint_trajectory_controller/joint_trajectory_controller.hpp
	both modified:   tricycle_controller/include/tricycle_controller/tricycle_controller.hpp

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[saikishor]

Lgtm

[Juliaj]

@saikishor @christophfroehlich , thank you for help review and merge my PR. Are any of these failures known? If they are new, i can help look into them shortly. lmk.

[saikishor]

Hello @Juliaj

The failures doesn't seem to be related.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 66.77%. Comparing base (0e79d1e) to head (b2cdaa5).
Report is 1 commits behind head on humble.

Additional details and impacted files

@@            Coverage Diff             @@
##           humble    #1482      +/-   ##
==========================================
+ Coverage   66.72%   66.77%   +0.05%     
==========================================
  Files         113      113              
  Lines       13337    13331       -6     
  Branches     8245     8245              
==========================================
+ Hits         8899     8902       +3     
+ Misses       1442     1436       -6     
+ Partials     2996     2993       -3     

Flag	Coverage Δ
unittests	66.77% <ø> (+0.05%)	⬆️

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

Files with missing lines	Coverage Δ
...de/diff_drive_controller/diff_drive_controller.hpp	100.00% <ø> (ø)
...iff_drive_controller/src/diff_drive_controller.cpp	73.64% <ø> (+0.49%)	⬆️
...jectory_controller/joint_trajectory_controller.hpp	100.00% <ø> (ø)
...ory_controller/src/joint_trajectory_controller.cpp	81.04% <ø> (+0.20%)	⬆️
...nclude/tricycle_controller/tricycle_controller.hpp	100.00% <ø> (ø)
tricycle_controller/src/tricycle_controller.cpp	66.56% <ø> (+0.38%)	⬆️

... and 2 files with indirect coverage changes

[christophfroehlich]

The failing tests are well known, no worries