Edit CODEOWNERS and JUnit XML file paths to match

[sarahchen6]

What does this PR do?
This PR removes the / prefix from the CODEOWNERS paths and the ./ prefix from the JUnit XML testcase source file paths.

Motivation:
Currently, all of our testcase codeowner tags in CI are incorrectly marked as the default @DataDog/ruby-guild. This is because the JUnit XML testcase source file paths do not match the CODEOWNERS paths. By removing the prefixes above, the paths will match and testcase codeowner tags will be properly set. See this reference for how testcase codeowner tag assignments work.

With proper codeowners assigned, we can better see the distribution and ownership of tests. This especially will help with identifying flaky test ownership.

Change log entry
No.

Additional Notes:
N/A

How to test the change?

1. CircleCI build-and-test workflow
2. any test, any run (e.g. test-3.4, run 0)
3. "Upload JUnit reports to Datadog" (e.g. for test-3.4, run 0)
4. Link under "Test runs report:" (e.g. for test-3.4, run 0)
5. "Test name" corresponds to the "Test code owners" (e.g. @DataDog/asm-ruby instead of @DataDog/ruby-guild)

This change should also show up in dashboards that filter on test codeowner tags (e.g. this dashboard under the "Test failure by codeowner" widget).

[datadog-datadog-prod-us1]

Datadog Report

Branch report: sarahchen6/edit-codeowners-to-correspond-with-sourcefile
Commit report: db85bf7
Test service: dd-trace-rb

✅ 0 Failed, 22100 Passed, 1476 Skipped, 5m 40.01s Total Time

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.73%. Comparing base (84ca739) to head (db85bf7).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4316   +/-   ##
=======================================
  Coverage   97.72%   97.73%           
=======================================
  Files        1365     1365           
  Lines       82727    82726    -1     
  Branches     4205     4205           
=======================================
+ Hits        80846    80849    +3     
+ Misses       1881     1877    -4     

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[pr-commenter]

Benchmarks

Benchmark execution time: 2025-01-23 21:04:02

Comparing candidate commit db85bf7 in PR branch sarahchen6/edit-codeowners-to-correspond-with-sourcefile with baseline commit 84ca739 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 31 metrics, 2 unstable metrics.