[WIP] fixes for pydantic>2.12

[atravitz]

following @mattwthompson's lead at: https://github.com/openforcefield/openff-interchange/pull/1501/changes

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[github-actions]

No API break detected ✅

[mattwthompson]

I'm not sure why the serialized representation changes - whether or not the default value of "nonbonded_cutoff" is serialized might not be important, but I've seen problems¹ in which a serialized non-default value is ignored and set to the default value².

The failures due to dependencies not being installed is just from the switch to the Conda package to the development install - cachetools, python-constraint, and xmltodict are probably all you need

Footnotes

1. https://github.com/openforcefield/openff-interchange/pull/1501#issuecomment-4545442911 ↩

2. Bad! ↩