fix(python): Set O_CLOEXEC on duplicated file descriptor

[ruihe774]

This is a minor fix for #17315.

Both Python and Rust set O_CLOEXEC for opened files. However, dup clears this flag. This PR uses F_DUPFD_CLOEXEC to explicitly make dupped fd non-inheritable.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.43%. Comparing base (daf2e49) to head (9658309).
Report is 14 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #17537      +/-   ##
==========================================
- Coverage   80.48%   80.43%   -0.06%     
==========================================
  Files        1483     1484       +1     
  Lines      195118   195342     +224     
  Branches     2778     2778              
==========================================
+ Hits       157039   157119      +80     
- Misses      37568    37711     +143     
- Partials      511      512       +1     

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