fix(instrumentation-xhr): resolve relative URLs before matching ignoreUrls

[Maximiliano-Zeballos]

Summary

• The XHR instrumentation was matching the raw URL from XMLHttpRequest.open() against ignoreUrls patterns
• Relative URLs (e.g. /api/data) would not match domain-based regex patterns (e.g. /.*myapp.*/)
• The Fetch instrumentation already resolves URLs to absolute form before checking, so this was inconsistent
• Fix: call parseUrl() before isUrlIgnored() in XHR, aligning behavior with Fetch

Test plan

• Added test case for relative URL with domain regex in ignoreUrls
• Existing tests remain unchanged

Fixes #5810

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Maximiliano-Zeballos / name: Maximiliano Zeballos (3c152f6, 95766f5)
• ✅ login: pichlermarc / name: Marc Pichler (0eef887, 37beace)

[overbalance]

Nice, thanks for the contribution! Please run lint:fix, commit the whitespace change, and make sure to include a changelog entry.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.74%. Comparing base (08c178e) to head (37beace).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6551   +/-   ##
=======================================
  Coverage   95.74%   95.74%           
=======================================
  Files         375      375           
  Lines       12820    12820           
  Branches     3056     3056           
=======================================
  Hits        12274    12274           
  Misses        546      546           

Files with missing lines	Coverage Δ
...emetry-instrumentation-xml-http-request/src/xhr.ts	97.61% <100.00%> (ø)

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[pichlermarc]

Looks like this got stalled even though it had browser maintainer approval because browser maintainers were not listed as codeowners for the changelog file.

I opened a PR to add them so that browser maintainers can independently merge these PRs in the future (#6622).

[otelbot]

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