Combine duplicate logic in Response.write_eof

[bdraco]

There were two branches that called await super().write_eof() that could be combined

[codspeed-hq]

CodSpeed Performance Report

Merging #9772 will not alter performance

_{Comparing write_eof (b84ec60) with master (e06dec3)}

Summary

✅ 15 untouched benchmarks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.67%. Comparing base (e06dec3) to head (b84ec60).
Report is 3 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9772      +/-   ##
==========================================
- Coverage   98.67%   98.67%   -0.01%     
==========================================
  Files         117      117              
  Lines       35958    35956       -2     
  Branches     4276     4275       -1     
==========================================
- Hits        35482    35480       -2     
  Misses        320      320              
  Partials      156      156              

Flag	Coverage Δ
CI-GHA	98.56% <100.00%> (-0.01%)	⬇️
OS-Linux	98.24% <100.00%> (-0.01%)	⬇️
OS-Windows	96.02% <100.00%> (-0.01%)	⬇️
OS-macOS	97.32% <100.00%> (-0.01%)	⬇️
Py-3.10.11	97.16% <100.00%> (-0.01%)	⬇️
Py-3.10.15	97.78% <100.00%> (-0.01%)	⬇️
Py-3.11.10	97.77% <100.00%> (-0.01%)	⬇️
Py-3.11.9	97.22% <100.00%> (-0.01%)	⬇️
Py-3.12.7	98.31% <100.00%> (-0.01%)	⬇️
Py-3.13.0	98.30% <100.00%> (+0.05%)	⬆️
Py-3.9.13	97.08% <100.00%> (-0.01%)	⬇️
Py-3.9.20	97.69% <100.00%> (+0.04%)	⬆️
Py-pypy7.3.16	97.26% <100.00%> (-0.01%)	⬇️
VM-macos	97.32% <100.00%> (-0.01%)	⬇️
VM-ubuntu	98.24% <100.00%> (-0.01%)	⬇️
VM-windows	96.02% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[patchback]

Backport to 3.10: 💚 backport PR created

✅ Backport PR branch: patchback/backports/3.10/eaa108609f4962ac0ee8e2c3347c010877d5d1bf/pr-9772

Backported as #9773

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 3.11: 💚 backport PR created

✅ Backport PR branch: patchback/backports/3.11/eaa108609f4962ac0ee8e2c3347c010877d5d1bf/pr-9772

Backported as #9774

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.