Don't validate data_out if it is empty (backport #391)

[mergify]

ros-controls/ros2_controllers#560 fails because filter_chains does not initialize intermediate output variables, which makes the assertion data_in.header.frame_id == data_out.header.frame_id fail.

I also changed the assertions to throwing exceptions, using fmt to concatenate numbers and strings.

---

This is an automatic backport of pull request #391 done by Mergify.

[mergify]

Cherry-pick of 04c1a2e has failed:

On branch mergify/bp/jazzy/pr-391
Your branch is up to date with 'origin/jazzy'.

You are currently cherry-picking commit 04c1a2e.
  (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:   control_toolbox/CMakeLists.txt
	modified:   control_toolbox/package.xml

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   control_toolbox/include/control_toolbox/filter_traits.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

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.70%. Comparing base (226ea4a) to head (a91083c).

Additional details and impacted files

@@           Coverage Diff           @@
##            jazzy     #406   +/-   ##
=======================================
  Coverage   74.70%   74.70%           
=======================================
  Files          29       29           
  Lines        1787     1787           
  Branches      106      106           
=======================================
  Hits         1335     1335           
  Misses        390      390           
  Partials       62       62           

Flag	Coverage Δ
unittests	74.70% <ø> (ø)

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[christophfroehlich]

@saikishor we havent backported #351?

[saikishor]

@saikishor we havent backported #351?

Ok. Sorry I missed that part