Ion: default hydrates=False in reduced_formula

[rkingsbury]

Summary

Major changes:

• default to hydrates=False in Ion.get_reduced_formula_and_factor()
• explicitly use Ion.get_reduced_formula_and_factor() rather than super().get_reduced_formula_and_factor() in `reduced_formula

Checklist

• Google format doc strings added. Check with ruff.
• Type annotations included. Check with mypy.
• Tests added for new features/fixes.

[janosh]

@rkingsbury Is this intentionally in draft mode?

[rkingsbury]

@janosh it was intentional, but I think it's good to go. All tests pass, but I wanted to make sure that this didn't mess up anything on the API side. When we re-did the Pourbaix ion data, I used Ion.reduced_formula as the database keys (the MPContribs identifiers). However, it doesn't appear that any of the ions in the dataset were formatted as hydrates (for example, Be3(OH)3[3+] is listed there, but could be written Be3OH2.1H2O).

In the API client, the only call is Ion.from_formula() (here) followed by Ion.composition so I don't think this change will cause any problems.