CI: Python 3.15.0rc1 builds

[paultiq]

This PR adds 3.15.0rc0 (cp315) to the packaging_wheels.yml matrix:

Changes:

• cibuildwheel to 4.2.0
• Add cp315 to matrix
• pyarrow 3.15 nightly index and markers for 3.15
• pandas 3.15 nightly index and markers for 3.15
• torch markers to restrict 3.15 tests to manylinux: since torch-cpu is only building manylinux 3.15 wheels
• Update a few other markers (adbc, gcsfs, polars) which are not yet 3.15 ready or are source builds
• restrict nanobind < 3.0: 3.0.0 introduced an unrelated breaking change (unrelated to 3.15)

Full matrix completed successfully on fork: https://github.com/paultiq/duckdb-python/actions/runs/33069017698

[paultiq]

Moving to draft for a moment: trying to minimize the change by removing the codspeed and polars marker changes...

edit: realized there's a Pandas deprecation issue when running the full test suite.

[paultiq]

Resolved "full" test failures: issue was some new Pandas 4 deprecation warnings related to deprecating inplace=true in a few places.

Passed on fork

* The coverage failure seems like it was introduced upstream in #522