[opencv4] Adjust/correct python path replacements

[Neumann-A]

Is your feature request related to a problem? Please describe.

Currently the opencv4 port does the following:

file(REMOVE_RECURSE "${CURRENT_PACKAGES_DIR}/${PYTHON3_SITE}/cv2/typing")
file(GLOB PYTHON3_SITE_FILES "${CURRENT_PACKAGES_DIR}/${PYTHON3_SITE}/cv2/*.py")
foreach(PYTHON3_SITE_FILE ${PYTHON3_SITE_FILES})
  vcpkg_replace_string("${PYTHON3_SITE_FILE}"
    "os.path.join('${CURRENT_PACKAGES_DIR}'"
    "os.path.join('.'"
    IGNORE_UNCHANGED
  )
  vcpkg_replace_string("${PYTHON3_SITE_FILE}"
    "os.path.join('${CURRENT_PACKAGES_DIR}/${PYTHON3_SITE}/cv2'"
    "os.path.join('.'"
    IGNORE_UNCHANGED
  )
endforeach()

Whoever replacing any path here with . seems incorrect to me. What should be done is change the path so that they are relative to the current script file instead.

The replacement also does not take care about external absolute paths like:

BINARIES_PATHS = [
    os.path.join('.', 'bin'),
    os.path.join(os.getenv('CUDA_PATH', 'D:/vcpkg_folders/no_msvc/installed/x64-windows/share/CUDAToolkit/../../compiler/cuda'), 'bin')
] + BINARIES_PATHS

observed in <packages>\tools\python3\Lib\site-packages\cv2\config.py

Proposed solution

Adjust the paths relativ to the file they are in.

Describe alternatives you've considered

No response

Additional context

No response