Fix DeprecationWarning by using np.arctan2 for element-wise array ope…

[laksh-krishna-sharma]

Fixs #4339 : DeprecationWarning in nuclinfo.py for NumPy 1.25+ Compatibility

This commit resolves a DeprecationWarning related to NumPy's handling of arrays with ndim > 0, which will raise an error in future releases. Specifically, the calculation of phase_ang has been updated to use np.arctan2, ensuring element-wise array operations are handled correctly.

Changes made in this Pull Request:

• Replaced the deprecated atan2(D, C) with np.arctan2(D, C) to avoid scalar conversion issues.
• Maintained the same logic for converting the angle to degrees.

This update ensures the codebase is future-proof for upcoming versions of NumPy.

PR Checklist

• [x] Tests?
• [x] Issue raised/referenced?

Developers certificate of origin

• [x] I certify that this contribution is covered by the LGPLv2.1+ license as defined in our LICENSE and adheres to the Developer Certificate of Origin.

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📚 Documentation preview 📚: https://mdanalysis--4730.org.readthedocs.build/en/4730/