refactor(instrumentation-express): update semconv usage to ATTR_ exports

[trentm]

Refs: #2377

[trentm]

Review note: Yes, this is changing from old HTTP semconv http.method to new stable HTTP semconv http.request.method. However, this is not testing that instr-express is generating this. It is just testing that the requestHook is being called. We could satisfy the test by using 'my.http.method' or 'foo' or whatever.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.69%. Comparing base (65a1389) to head (d956a5d).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2859      +/-   ##
==========================================
+ Coverage   89.65%   89.69%   +0.04%     
==========================================
  Files         185      185              
  Lines        9034     9034              
  Branches     1852     1852              
==========================================
+ Hits         8099     8103       +4     
+ Misses        935      931       -4     

Files with missing lines	Coverage Δ
...try-instrumentation-express/src/instrumentation.ts	96.75% <100.00%> (ø)

... and 1 file with indirect coverage changes

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