fix(instrumentation-aws-lambda): do not import from semantic-conventions incubating entry-point

[trentm]

Refs: https://github.com/open-telemetry/opentelemetry-js/tree/main/semantic-conventions#unstable-semconv

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.80%. Comparing base (4fb610d) to head (5982a41).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2670   +/-   ##
=======================================
  Coverage   90.80%   90.80%           
=======================================
  Files         170      171    +1     
  Lines        8070     8071    +1     
  Branches     1646     1646           
=======================================
+ Hits         7328     7329    +1     
  Misses        742      742           

Files with missing lines	Coverage Δ
...-instrumentation-aws-lambda/src/instrumentation.ts	94.52% <100.00%> (ø)
...elemetry-instrumentation-aws-lambda/src/semconv.ts	100.00% <100.00%> (ø)

[pichlermarc]

(approving due to owner-approval)