Fixes #27563. Extends make_optional_arg to support making multiple arguments optional, and overload sets with different parameter names (for findEssentialMat).

Example before patch:

def getOptimalNewCameraMatrix(cameraMatrix: cv2.typing.MatLike, distCoeffs: cv2.typing.MatLike, imageSize: cv2.typing.Size, alpha: float, newImgSize: cv2.typing.Size = ..., centerPrincipalPoint: bool = ...) -> tuple[cv2.typing.MatLike, cv2.typing.Rect]: ...

Example after patch:

def getOptimalNewCameraMatrix(cameraMatrix: cv2.typing.MatLike, distCoeffs: cv2.typing.MatLike | None, imageSize: cv2.typing.Size, alpha: float, newImgSize: cv2.typing.Size = ..., centerPrincipalPoint: bool = ...) -> tuple[cv2.typing.MatLike, cv2.typing.Rect]: ...

I wonder if introducing a new modifier, to the effect of "argument is nullable", in C++ would be better than adding these API refinements...

Pull Request Readiness Checklist

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• 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