Update pyo3 in conjunction with arrow2::arrow and arrow-rs::pyarrow support

[jleibs]

What

In preparation of:

• Python API to get dataframes out of an RRD #6811

We want to be able to use the arrow-rs pyarrow support to more easily move data bidirectionally between rust and python.

This required updating our pyo3 version, which required migrating some functions to use the new Bound<> APIs.

This allowed us to get rid of the old unsafe calls, though adds an extra step of going pyarrow -> arrow-rs -> arrow.

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!
• If have noted any breaking changes to the log API in CHANGELOG.md and the migration guide

• PR Build Summary
• Recent benchmark results
• Wasm size tracking

To run all checks from main, comment on the PR with @rerun-bot full-check.

[teh-cmc]

@rerun-bot full-check

[github-actions]

Started a full build: https://github.com/rerun-io/rerun/actions/runs/10646522823

[teh-cmc]

@rerun-bot full-check

[github-actions]

Started a full build: https://github.com/rerun-io/rerun/actions/runs/10646592777

[teh-cmc]

Fantastic -- let's get this in sooner than later, we can release re_arrow2 at any time.