For pydantic 2 with Evidently, upgrade to 0.4.16 or later; older releases are pinned to pydantic 1 by the FastAPI-based UI service. The pyarrow pin is gone too (replaced by pandas[parquet]), so let pandas choose the pyarrow version.

Context: Evidently issue #862 (closed): users needed pydantic v2 and newer pyarrow. Maintainers mike0sv and emeli-dral explained the constraints: the pyarrow dependency was removed in #885 and replaced with pandas[parquet], so any pyarrow version pandas accepts works. Pydantic v2 support landed in Evidently 0.4.16; earlier the UI service's FastAPI dependency blocked the bump. Upgrade to 0.4.16 or later for pydantic 2.