refactor(rust): Recursively evaluate is_elementwise for function expressions

[orlp]

This fixes issues that the new streaming engine had, such as this:

>>> df = pl.DataFrame({"x": [1, 2, 3]})
>>> df.select(pl.col.x.max().sin())
shape: (1, 1)
┌─────────┐
│ x       │
│ ---     │
│ f64     │
╞═════════╡
│ 0.14112 │
└─────────┘
>>> df.lazy().select(pl.col.x.max().sin()).collect(new_streaming=True)
shape: (3, 1)
┌──────────┐
│ x        │
│ ---      │
│ f64      │
╞══════════╡
│ 0.841471 │
│ 0.909297 │
│ 0.14112  │
└──────────┘

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 45 lines in your changes missing coverage. Please review.

Project coverage is 79.79%. Comparing base (19a30ed) to head (007001c).
Report is 66 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-stream/src/physical_plan/lower_ir.rs	0.00%	21 Missing ⚠️
...ates/polars-stream/src/physical_plan/lower_expr.rs	0.00%	12 Missing ⚠️
crates/polars-stream/src/physical_plan/mod.rs	0.00%	10 Missing ⚠️
crates/polars-stream/src/skeleton.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18385      +/-   ##
==========================================
- Coverage   79.84%   79.79%   -0.05%     
==========================================
  Files        1496     1497       +1     
  Lines      200338   200391      +53     
  Branches     2841     2841              
==========================================
- Hits       159951   159900      -51     
- Misses      39862    39966     +104     
  Partials      525      525              

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