quic: truncate CONNECTION_CLOSE frame reason field

[efekrskl]

Long reason strings inside a CONNECTION_CLOSE frame could exceed the space available and crash the process.

This PR limits the reason string to 256 UTF-8 bytes. Any string longer than the limit will get truncated. Also adds new tests and updates the documentation.

I think 256 bytes is a sensible default because the default maximum UDP datagram payload size is 1200 bytes. Before the handshake ngtcp2 can coalesce packets, encoding the same reason with 768 (3x256) bytes at most, this should leave enough headroom. This also matches Google QUICHE's limit

[nodejs-github-bot]

Review requested:

• @nodejs/quic

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.44%. Comparing base (c0daf39) to head (b1f7e9e).
⚠️ Report is 12 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66644      +/-   ##
==========================================
+ Coverage   90.43%   90.44%   +0.01%     
==========================================
  Files         791      791              
  Lines      276593   276816     +223     
  Branches    53112    53195      +83     
==========================================
+ Hits       250126   250375     +249     
+ Misses      16867    16837      -30     
- Partials     9600     9604       +4     

see 41 files with indirect coverage changes

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[inoway46]

https://github.com/nodejs/node/actions/runs/38052685564/job/114214912806
This build failure has been fixed in #66603.