feat: Add negative slicing to new streaming multiscan

[coastalwhite]

Built on #21191.

[codecov]

Codecov Report

Attention: Patch coverage is 90.76923% with 42 lines in your changes missing coverage. Please review.

Project coverage is 79.90%. Comparing base (d6bb315) to head (38ef3a6).
Report is 36 commits behind head on main.

Files with missing lines	Patch %	Lines
...s/polars-stream/src/nodes/io_sources/multi_scan.rs	91.80%	35 Missing ⚠️
.../polars-stream/src/nodes/io_sources/parquet/mod.rs	66.66%	3 Missing ⚠️
crates/polars-stream/src/nodes/io_sources/mod.rs	84.61%	2 Missing ⚠️
crates/polars-stream/src/nodes/io_sources/csv.rs	66.66%	1 Missing ⚠️
crates/polars-stream/src/nodes/io_sources/ipc.rs	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #21219      +/-   ##
==========================================
- Coverage   79.92%   79.90%   -0.02%     
==========================================
  Files        1596     1596              
  Lines      228746   228705      -41     
  Branches     2616     2618       +2     
==========================================
- Hits       182823   182754      -69     
- Misses      45324    45352      +28     
  Partials      599      599              

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