refactor(rust): Add output_schema to all PhysNodes

[orlp]

This is necessary for lowering expressions, we need to be able to get the schema of arbitrary PhysNodes.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 22 lines in your changes missing coverage. Please review.

Project coverage is 80.22%. Comparing base (c88da1f) to head (9a65d73).
Report is 43 commits behind head on main.

Files	Patch %	Lines
crates/polars-stream/src/skeleton.rs	0.00%	8 Missing ⚠️
crates/polars-stream/src/physical_plan/lower_ir.rs	0.00%	6 Missing ⚠️
crates/polars-stream/src/physical_plan/mod.rs	0.00%	6 Missing ⚠️
crates/polars-plan/src/plans/ir/schema.rs	0.00%	1 Missing ⚠️
crates/polars-stream/src/physical_plan/to_graph.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #18272   +/-   ##
=======================================
  Coverage   80.21%   80.22%           
=======================================
  Files        1500     1501    +1     
  Lines      198897   198908   +11     
  Branches     2837     2837           
=======================================
+ Hits       159547   159572   +25     
+ Misses      38822    38808   -14     
  Partials      528      528           

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