fix: Properly broadcast array arithmetic

[ritchie46]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 2 lines in your changes missing coverage. Please review.

Project coverage is 79.89%. Comparing base (dcad7d8) to head (59aa08e).
Report is 67 commits behind head on main.

Files with missing lines	Patch %	Lines
...ates/polars-core/src/series/arithmetic/borrowed.rs	85.71%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #18851   +/-   ##
=======================================
  Coverage   79.88%   79.89%           
=======================================
  Files        1519     1519           
  Lines      205820   205831   +11     
  Branches     2897     2897           
=======================================
+ Hits       164415   164440   +25     
+ Misses      40857    40843   -14     
  Partials      548      548           

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