fix(instrumentation,instrumentation-http): fix codecov under-reporting

[mwear]

Which problem is this PR solving?

I found this while working on #6864. Coverage for instrumentation and instrumentation-http was under-reported on Codecov. Both packages run their CJS and ESM (and double-instr) suites as separate nyc invocations. By default each nyc run cleans .nyc_output before running and writes a report after, so the later run wiped the earlier run's data and the final coverage-final.json reflected only the last suite.

Short description of the changes

• Add --no-clean to the follow-on test runs so raw coverage accumulates in .nyc_output instead of being wiped.
• Add a trailing nyc report to the test script to emit the merged report Codecov consumes.
• Add --silent to the per-suite runs to suppress the partial intermediate reports.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Ran npm test in both packages and confirmed the resulting coverage-final.json includes coverage from all suites (CJS + ESM + double-instr) rather than only the final run.

Checklist:

• Followed the style guidelines of this project

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.14%. Comparing base (d61ab5f) to head (67b6c2e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6867      +/-   ##
==========================================
- Coverage   95.58%   95.14%   -0.45%     
==========================================
  Files         388      397       +9     
  Lines       13170    14248    +1078     
  Branches     3005     3296     +291     
==========================================
+ Hits        12589    13556     +967     
- Misses        581      692     +111     

see 11 files with indirect coverage changes

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[pichlermarc]

thank you 🙂