calib3d: improve fisheye extrinsic refinement - #29940

Description

Related: #23962

Improve fisheye extrinsic refinement for ill-conditioned views and poorly
scaled object points. The previous hand-crafted and numerically fragile
Gauss-Newton solver could fail for near-collinear views and small
object-point scales.

This also improves code reuse by replacing the custom Gauss-Newton solver with
the existing Levenberg-Marquardt implementation. Translation parameters are
normalized to make convergence less sensitive to object-point scale.

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 OpenCV 4.x branch under the Apache 2 License.
• To the best of my knowledge, this patch is not based on GPL-incompatible code.
• The PR is proposed to the proper branch.
• There is a reference to related work: Unreliable behaviour of cv::fisheye::calibrate #23962.
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable.
  Synthetic accuracy and degeneracy tests are included. No external test data is required.
• The feature is well documented and sample code can be built with the project CMake.