fix(h2): ignore late data frames after request completion

[mcollina]

Description

Fixes a crash in the HTTP/2 dispatcher when a late data event arrives after the request has already completed.

In client-h2, stream.on('data') called request.onData() unconditionally. If completion happened first (for example via trailers), request.onData() could hit the internal assert(!this.completed) and crash the process.

This change:

• Adds an early return in the H2 data handler when request.aborted || request.completed
• Removes data listeners before invoking request.onComplete(trailers) in the trailers path
• Adds a regression test that simulates response -> trailers -> late data

Fixes: #4843

Testing

• npx borp -p "test/http2-late-data.js"
• npx borp -p "test/http2-trailers.js"
• npx borp -p "test/http2-dispatcher.js"
• npm run lint

[hxinhan]

Should we also check if request is complete here?

[hxinhan]

Thanks for looking into this bug report. I left a comment about potential request completion check in additional call path

[codecov-commenter]

Codecov Report

❌ Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.13%. Comparing base (0a23610) to head (e9b08c5).
⚠️ Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/dispatcher/client-h2.js	60.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4845      +/-   ##
==========================================
- Coverage   93.19%   93.13%   -0.06%     
==========================================
  Files         109      109              
  Lines       34222    34244      +22     
==========================================
+ Hits        31893    31894       +1     
- Misses       2329     2350      +21     

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[hxinhan]

Should we merge the PR now?