chore: Bump latest polars version to v1.43

[Oliver Borchert (borchero)]

Motivation

I wanted to check whether pola-rs/polars#28341 results in faster lazy evaluation of collection filtering. Indeed, when setting POLARS_ALLOW_NESTED_CSPE=1, we see no significant diff between eager and lazy evaluation 🚀

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (e4353e7) to head (9a8d38c).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

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##              main      #369   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           56        56           
  Lines         3506      3507    +1     
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+ Hits          3506      3507    +1     

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[Copilot]

Pull request overview

This PR updates the “latest polars” Pixi environment to polars 1.43.* and adjusts the repo’s benchmarks/test configuration to accommodate behavioral changes observed when evaluating eager vs lazy collection filtering.

Changes:

• Bump feature.polars-latest from polars 1.41.* to 1.43.* (and update pixi.lock accordingly).
• Add a new benchmark that exercises Collection.filter(..., eager=False) and forces evaluation via collect_all().
• Silence a newly encountered Polars deprecation warning in pytest configuration.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 2 comments.

File	Description
tests/benches/test_collection.py	Adds a benchmark for lazy (eager=False) collection filtering and collection via collect_all().
pyproject.toml	Adds a filterwarnings entry to ignore a Polars concat deprecation warning.
pixi.toml	Updates feature.polars-latest to polars = "1.43.*".
pixi.lock	Regenerates the lockfile to reflect the Polars 1.43.x upgrade across platforms.