fix: Broadcast zip_with for structs

[coastalwhite]

Fixes #18673.

[codecov]

Codecov Report

Attention: Patch coverage is 77.77778% with 8 lines in your changes missing coverage. Please review.

Project coverage is 79.85%. Comparing base (962b576) to head (abd2f3e).
Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-core/src/chunked_array/ops/zip.rs	77.77%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18770      +/-   ##
==========================================
- Coverage   79.86%   79.85%   -0.01%     
==========================================
  Files        1517     1518       +1     
  Lines      205542   205612      +70     
  Branches     2892     2892              
==========================================
+ Hits       164156   164196      +40     
- Misses      40838    40868      +30     
  Partials      548      548              

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