fix(python): Fix retries parameter in scan functions not taking effect when it was set to 0

[stinodego]

I ran into this while writing tests for #17532

Changes

• Set default retries to 2 to align with the Rust side
• Make sure setting retries=0 works correctly

[codecov]

Codecov Report

Attention: Patch coverage is 93.75000% with 1 line in your changes missing coverage. Please review.

Project coverage is 80.54%. Comparing base (a55d9bc) to head (1ca685d).
Report is 1 commits behind head on main.

Files	Patch %	Lines
py-polars/src/lazyframe/mod.rs	91.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #17564      +/-   ##
==========================================
+ Coverage   80.49%   80.54%   +0.04%     
==========================================
  Files        1483     1483              
  Lines      195171   195189      +18     
  Branches     2778     2778              
==========================================
+ Hits       157099   157210     +111     
+ Misses      37561    37468      -93     
  Partials      511      511              

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