integrateVolumeUnit fix

[DumDereDum]

Pull Request Readiness Checklist

Replace int with Point3i at integrateVolumeUnit signature

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 other license that is incompatible with OpenCV
• The PR is proposed to proper branch
• There is reference to 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

[savuor]

👍

[alalek]

Please take a look on broken Debug build.

[savuor]

Now the problem's resolved

[savuor]

👍