[PR #11106/cfb9931 backport][3.13] Fix cookies with duplicate names being lost when updating cookie jar

[bdraco]

(cherry picked from commit cfb9931)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.25%. Comparing base (b2242d6) to head (146b917).
Report is 1 commits behind head on 3.13.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff            @@
##             3.13   #11109    +/-   ##
========================================
  Coverage   98.25%   98.25%            
========================================
  Files         130      130            
  Lines       41777    41999   +222     
  Branches     2293     2300     +7     
========================================
+ Hits        41046    41267   +221     
  Misses        557      557            
- Partials      174      175     +1     

Flag	Coverage Δ
CI-GHA	98.14% <100.00%> (+<0.01%)	⬆️
OS-Linux	97.88% <100.00%> (+<0.01%)	⬆️
OS-Windows	95.50% <100.00%> (+0.02%)	⬆️
OS-macOS	97.09% <100.00%> (+<0.01%)	⬆️
Py-3.10.11	96.86% <100.00%> (+<0.01%)	⬆️
Py-3.10.17	97.36% <100.00%> (+<0.01%)	⬆️
Py-3.11.12	97.55% <100.00%> (+0.05%)	⬆️
Py-3.11.9	97.04% <100.00%> (+0.01%)	⬆️
Py-3.12.10	97.90% <100.00%> (+0.01%)	⬆️
Py-3.13.3	97.89% <100.00%> (+<0.01%)	⬆️
Py-3.9.13	96.76% <100.00%> (+0.02%)	⬆️
Py-3.9.22	97.26% <100.00%> (+0.01%)	⬆️
Py-pypy7.3.16	86.68% <100.00%> (+0.10%)	⬆️
VM-macos	97.09% <100.00%> (+<0.01%)	⬆️
VM-ubuntu	97.88% <100.00%> (+<0.01%)	⬆️
VM-windows	95.50% <100.00%> (+0.02%)	⬆️

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[codspeed-hq]

CodSpeed Performance Report

Merging #11109 will not alter performance

_{Comparing patchback/backports/3.13/cfb99316e1fd89943b1f6c3793d286629b7acc3d/pr-11106 (146b917) with 3.13 (b2242d6)}

Summary

✅ 59 untouched benchmarks