refactor(python): Pass through missing rolling and stringfunction information in pyir

[wence-]

We missed these when first introducing the transliteration.

Make a small breaking change as well by aligning the names of function expressions to match those that are used in the public python Expr API.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 39 lines in your changes missing coverage. Please review.

Project coverage is 80.50%. Comparing base (235cad3) to head (342c545).
Report is 55 commits behind head on main.

Files	Patch %	Lines
py-polars/src/lazyframe/visitor/expr_nodes.rs	0.00%	39 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #17702      +/-   ##
==========================================
+ Coverage   80.37%   80.50%   +0.13%     
==========================================
  Files        1500     1504       +4     
  Lines      196605   197182     +577     
  Branches     2793     2806      +13     
==========================================
+ Hits       158016   158739     +723     
+ Misses      38076    37922     -154     
- Partials      513      521       +8     

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