http2: emit error on canceled streams when aborted event is not emitted

[mcollina]

When a client HTTP/2 stream's writable side is already ended (e.g. GET requests), receiving RST code 8 (NGHTTP2_CANCEL) emitted neither the aborted nor the error event, causing the stream to close silently.

The fix only skips error generation for NGHTTP2_CANCEL when the aborted event was actually emitted.

Fixes: #56627

[nodejs-github-bot]

Review requested:

• @nodejs/http2
• @nodejs/net

[codecov]

Codecov Report

❌ Patch coverage is 82.60870% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.66%. Comparing base (58a8e1d) to head (f3dd59d).
⚠️ Report is 98 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/http2/core.js	82.60%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #62923      +/-   ##
==========================================
- Coverage   89.69%   89.66%   -0.04%     
==========================================
  Files         706      706              
  Lines      218222   219419    +1197     
  Branches    41768    42077     +309     
==========================================
+ Hits       195731   196735    +1004     
- Misses      14411    14602     +191     
- Partials     8080     8082       +2     

Files with missing lines	Coverage Δ
lib/internal/http2/core.js	95.16% <82.60%> (-0.09%)	⬇️

... and 90 files with indirect coverage changes

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