fix: Always use cloudpickle for the python objects in cloud plans

[coastalwhite]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 92.94118% with 6 lines in your changes missing coverage. Please review.

Project coverage is 81.57%. Comparing base (727dd4c) to head (0b694ce).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-utils/src/pl_serialize.rs	92.68%	3 Missing ⚠️
...rates/polars-plan/src/dsl/python_dsl/python_udf.rs	90.47%	2 Missing ⚠️
crates/polars-plan/src/client/mod.rs	83.33%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #23474   +/-   ##
=======================================
  Coverage   81.57%   81.57%           
=======================================
  Files        1634     1634           
  Lines      221194   221204   +10     
  Branches     2813     2813           
=======================================
+ Hits       180443   180458   +15     
+ Misses      40060    40055    -5     
  Partials      691      691           

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