feat(aws-lambda)!: Remove explicit x-ray context in favor of global propagator

[martinkuba]

This is part of open-telemetry/opentelemetry-js#4494

Currently, the instrumentation is explicitly retrieving context from the X-Ray _X_AMZN_TRACE_ID environment variable. It is possible now to handle this using the xray-lambda propagator, which is the approach described in the specification.

This change removes the explicit handling including the disableAwsContextPropagation configuration option.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.83%. Comparing base (1ae98de) to head (310c7fe).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2369      +/-   ##
==========================================
- Coverage   90.85%   90.83%   -0.03%     
==========================================
  Files         159      159              
  Lines        7853     7831      -22     
  Branches     1622     1610      -12     
==========================================
- Hits         7135     7113      -22     
  Misses        718      718              

Files with missing lines	Coverage Δ
...-instrumentation-aws-lambda/src/instrumentation.ts	94.57% <100.00%> (-0.64%)	⬇️

[blumamir]

Thanks @martinkuba .
Great to see this cleaned up, aligned to spec and simplified.

The changes LGTM, I am a bit worried that existing users might not be aware if they should actively take action or will potentially break when upgrading to this new version.

Please mark it as breaking and consider adding some more guidance and examples in the README on how to use it correctly.

[blumamir]

Thanks @martinkuba this looks great!

Added 2 minor comments about some cleanups that I think we need to apply before merging