Fix server disconnect when error after 100-continue (#8876)

[Dreamsorcerer]

(cherry picked from commit e058cbd)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.70%. Comparing base (4179aba) to head (af2531e).
Report is 216 commits behind head on 3.10.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             3.10    #8900   +/-   ##
=======================================
  Coverage   97.70%   97.70%           
=======================================
  Files         108      108           
  Lines       34206    34215    +9     
  Branches     4066     4067    +1     
=======================================
+ Hits        33422    33431    +9     
  Misses        586      586           
  Partials      198      198           

Flag	Coverage Δ
CI-GHA	97.60% <100.00%> (+<0.01%)	⬆️
OS-Linux	97.27% <100.00%> (-0.01%)	⬇️
OS-Windows	94.83% <100.00%> (+<0.01%)	⬆️
OS-macOS	96.96% <100.00%> (+<0.01%)	⬆️
Py-3.10.11	97.05% <100.00%> (+<0.01%)	⬆️
Py-3.10.14	96.98% <100.00%> (+<0.01%)	⬆️
Py-3.11.9	97.22% <100.00%> (+<0.01%)	⬆️
Py-3.12.4	94.63% <100.00%> (+<0.01%)	⬆️
Py-3.12.5	97.02% <100.00%> (+<0.01%)	⬆️
Py-3.8.10	94.46% <100.00%> (+<0.01%)	⬆️
Py-3.8.18	96.79% <100.00%> (+<0.01%)	⬆️
Py-3.9.13	96.95% <100.00%> (+<0.01%)	⬆️
Py-3.9.19	96.89% <100.00%> (+<0.01%)	⬆️
Py-pypy7.3.16	96.48% <100.00%> (+<0.01%)	⬆️
VM-macos	96.96% <100.00%> (+<0.01%)	⬆️
VM-ubuntu	97.27% <100.00%> (-0.01%)	⬇️
VM-windows	94.83% <100.00%> (+<0.01%)	⬆️

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