Update OpenCV patches and HAL

* CMake's standard <PROJECT-NAME>_SOURCE_DIR can be used instead of
  creating a new OPENCV_SOURCE_DIR. See
  https://cmake.org/cmake/help/latest/variable/PROJECT-NAME_SOURCE_DIR.html
* Connect to the new HAL function that has been added to OpenCV that
  matches the Gaussian blur provided by KleidiCV.
  See https://github.com/opencv/opencv/pull/25397
* Rename cv_hal_transpose to cv_hal_transpose2d to match
  https://github.com/opencv/opencv/pull/25342