Experiment with new JNI-based Kotlin bindgen

Opening this issue to make sure we don't forget to check it out when this becomes available! Currently on main on uniffi-rs. This would be opt-in as far as I understand it, so upgrading to the 0.32 or 0.33 version of uniffi wouldn't automatically use this (but they haven't released yet so still needs to be checked once they release).

See mozilla/uniffi-rs#2911. Better stability and in many benchmarks, 100x improvement in performance.

Downside is I think this would create some breaking changes on function signatures and types like records, enums, and options. Not sure yet.

Start by reviewing mozilla/uniffi-rs#2911 and checking the uniffi 0.32 or 0.33 release when available. Assess whether the JNI-based Kotlin bindgen can be enabled on main, which function signatures and record, enum, or option types would change, and document the compatibility decision.

Written by the indexing model from the issue text.