[diff_drive] Remove unused parameter and add simple validation #abi-breaking (backport #958)

[mergify]

This is an automatic backport of pull request #958 done by Mergify.
Cherry-pick of 2705ca8 has failed:

On branch mergify/bp/iron/pr-958
Your branch is up to date with 'origin/iron'.

You are currently cherry-picking commit 2705ca8.
  (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/CMakeLists.txt
	modified:   diff_drive_controller/include/diff_drive_controller/diff_drive_controller.hpp
	modified:   diff_drive_controller/src/diff_drive_controller.cpp
	modified:   diff_drive_controller/src/diff_drive_controller_parameter.yaml
	modified:   diff_drive_controller/test/config/test_diff_drive_controller.yaml
	modified:   diff_drive_controller/test/test_load_diff_drive_controller.cpp

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   diff_drive_controller/test/test_diff_drive_controller.cpp

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

---

Mergify commands and options

More conditions and actions can be found in the documentation.

You can also trigger Mergify actions by commenting on this pull request:

• @Mergifyio refresh will re-evaluate the rules
• @Mergifyio rebase will rebase this PR on its base branch
• @Mergifyio update will merge the base branch into this PR
• @Mergifyio backport <destination> will backport this PR on <destination> branch

Additionally, on Mergify dashboard you can:

• look at your merge queues
• generate the Mergify configuration with the config editor.

Finally, you can contact us on https://mergify.com

[bmagyar]

I'm fixing up the tests here. It requires a slightly different approach as we can't use the initcontroller shortcut that well here

[christophfroehlich]

in favor of #1056