feat(python): Expose temporal function expression ops to expr ir

[wence-]

Also align a few more of the string names with the name used in the expression API that eventually leads to construction of these nodes.

[codecov]

Codecov Report

Attention: Patch coverage is 1.23457% with 80 lines in your changes are missing coverage. Please review.

Project coverage is 81.47%. Comparing base (27c6dcd) to head (83a540d).
Report is 3 commits behind head on main.

❗ Current head 83a540d differs from pull request most recent head 494fa9c

Please upload reports for the commit 494fa9c to get more accurate results.

Files	Patch %	Lines
py-polars/src/lazyframe/visitor/expr_nodes.rs	0.00%	80 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16546      +/-   ##
==========================================
- Coverage   81.50%   81.47%   -0.04%     
==========================================
  Files        1412     1412              
  Lines      185246   185210      -36     
  Branches     2985     2987       +2     
==========================================
- Hits       150987   150892      -95     
- Misses      33741    33800      +59     
  Partials      518      518              

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