Remove useless C headers

[vrabaud]

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake

[vrabaud]

@mshabunin , this is similar to opencv/opencv#26763 . The "default" CI failure was before I pushed fixes to opencv/opencv

[mshabunin]

It looks like a strange merge issue - CI uses your remove_c branch from the opencv repository and results of merge on GHA and buildbot are different. Please try to remove remove_c branch from your opencv fork and force push to this PR to restart CI builds.

[vrabaud]

Done, it seems to pass now