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

…upport (#7322)

In preparation of:
- #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.