chore: update thiserror to 2.0 (#12407)

While at the moment this is strictly a change that introduces extra
dependencies and shuffling, over time we expect the ecosystem to start
moving towards 2.0 bit by bit, and any new improvements to the crate to
only go to the 2.0 series.

Changelog: https://github.com/dtolnay/thiserror/releases/tag/2.0.0