refactor(instr-http): use exported strings for semconv

[JamieDanielson]

Which problem is this PR solving?

Updates #4567

Short description of the changes

• Replace SemanticAttributes.*, NetTransportValues.*, and HttpFlavorValues.* with specific exported strings for http instrumentation package.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Not quite sure; chore to replace deprecated fields but feature to improve minification?

How Has This Been Tested?

• unit tests

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

Merging #4573 (49364df) into main (6547440) will increase coverage by 0.01%.
The diff coverage is 97.36%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4573      +/-   ##
==========================================
+ Coverage   92.83%   92.84%   +0.01%     
==========================================
  Files         328      328              
  Lines        9487     9487              
  Branches     2035     2035              
==========================================
+ Hits         8807     8808       +1     
+ Misses        680      679       -1     

Files	Coverage Δ
...ges/opentelemetry-instrumentation-http/src/http.ts	93.37% <100.00%> (ø)
...es/opentelemetry-instrumentation-http/src/utils.ts	98.81% <97.22%> (ø)

... and 1 file with indirect coverage changes

[pichlermarc]

Looks good, just missing a changelog entry (conventional commit type might be refactor as opposed to chore) 🙂

Thanks for taking care of this 👍