fix(event_handler): sync middleware receives real response in async ASGI context

[leandrodamascena]

Issue number: Closes #7981

The fix runs sync middlewares in a separate thread. When the middleware calls next(app), we intercept that call, resolve the async handler on the event loop, and pass the real response back to the thread. This way both request validation (pre-processing) and response validation (post-processing) see the actual data.

Changes

• Rewrote _wrap_middleware_async in http_resolver.py to use thread-based coordination between sync middlewares and async handlers
• Removed @pytest.mark.skip from existing async validation test
• Added tests for async handler response validation (422)
• Added tests for sync handlers called via ASGI with validation (200 and 422)

User experience

Please share what the user experience looks like before and after this change

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.73%. Comparing base (2b95d7f) to head (e58c97e).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #8089      +/-   ##
===========================================
+ Coverage    96.63%   96.73%   +0.10%     
===========================================
  Files          283      283              
  Lines        13862    13881      +19     
  Branches      1111     1111              
===========================================
+ Hits         13395    13428      +33     
+ Misses         342      331      -11     
+ Partials       125      122       -3     

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[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud