test(instr-http): remove usages of new Span

[david-luna]

Which problem is this PR solving?

The Span constructor from ' @opentelemetry/sdk-trace-base` is planned for removal from the public API . This PR anticipates the possible breaking changes derived from it

Refs #3597

Short description of the changes

• Remove usage of new Span constructor in favour of using a mock Span and asserting over API calls

Type of change

Please delete options that are not relevant.

• Test refactor (non-breaking change which fixes tests)

How Has This Been Tested?

• Ran intr-http unit tests

Checklist:

• Followed the style guidelines of this project
• Unit tests have been modified

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.26%. Comparing base (f8ab559) to head (82dbd0b).
Report is 26 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5035      +/-   ##
==========================================
- Coverage   93.39%   93.26%   -0.14%     
==========================================
  Files          46      317     +271     
  Lines         712     8194    +7482     
  Branches      120     1640    +1520     
==========================================
+ Hits          665     7642    +6977     
- Misses         47      552     +505     

see 266 files with indirect coverage changes

[pichlermarc]

Looks great, thanks 🙂