Dependency specification missing for python3.14

There is no case defined for `numpy` using `python3.14` in `pyproject.toml`. As a result, installing packages that depend on `opencv-python` and a newer version of `numpy` does not work as expected and causes conflicts between `numpy` versions.

https://github.com/opencv/opencv-python/blob/81b4c07a3a29bdc6df70da84358b63ba1d656aae/pyproject.toml#L5