[ur_controllers] Remove Werror from CMakeLists (backport #1720)

[mergify]

While this might be good for CI reasons, this has broken our buildfarm builds a couple of times over the last years due to upstream warnings.

Removing this from the CMakeLists would not affect buildfarm builds, while we can still enable this in CI if we want.

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This is an automatic backport of pull request #1720 done by Mergify.

[mergify]

Cherry-pick of 2fb2d5a has failed:

On branch mergify/bp/humble/pr-1720 Your branch is up to date with 'origin/humble'. You are currently cherry-picking commit 2fb2d5a. (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: ur_robot_driver/include/ur_robot_driver/hardware_interface.hpp Unmerged paths: (use "git add/rm <file>..." as appropriate to mark resolution)	deleted by us: .github/workflows/reusable_ici.yml	both modified: ur_controllers/CMakeLists.txt 

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