Narwhals v1.43.0

Changes

• ci: xfail polars_lazy[gpu] to make CI green (#2685)
• docs,tests: Test and document kleene logic for boolean columns (#2682)
• test: Suppress too_slow on test_rolling_var_hypothesis_polars (#2674)

⚠️ Deprecations

• depr: Deprecate nw.get_level from main namespace (#2681)

✨ Enhancements

• feat: raise informative error or warning when passing narwhals object to nw.dependencies.is_*_dataframe and nw.dependencies.is_*_series (#1444)
• feat: add Expr.kurtosis and Series.kurtosis (#2676)
• feat: add Expr.sqrt and Series.sqrt (#2668)

🛠️ Other improvements

• chore: Remove unused utility functions (#2677)
• refactor: Simplify Implementation.to_native_namespace (#2620)

Thank you to all our contributors for making this release possible!
@FBruzzesi, @MarcoGorelli, @dangotbanned and @raisadz