[NO-TICKET] Adjust leaking thread detection for new Rails

[Strech]

What does this PR do?

This will fix the warning about the leaking threads in the tests for ActiveRecord connection reaper.

Motivation:

Result of the discussion with guild regarding that issue. It turns out we already was ignoring the reaper, but only for the older versions of ActiveRecord.

Change log entry

No. Internal change

Additional Notes:

None.

How to test the change?

CI

[datadog-datadog-prod-us1]

Datadog Report

Branch report: fix-leaking-thread-detection-for-connection-reaper
Commit report: f851bc4
Test service: dd-trace-rb

✅ 0 Failed, 20629 Passed, 1370 Skipped, 3m 18.34s Total Time

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-03-12 08:30:01

Comparing candidate commit f851bc4 in PR branch fix-leaking-thread-detection-for-connection-reaper with baseline commit 65b2901 in branch master.

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

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.68%. Comparing base (65b2901) to head (f851bc4).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4481      +/-   ##
==========================================
- Coverage   97.70%   97.68%   -0.02%     
==========================================
  Files        1379     1379              
  Lines       83881    83880       -1     
  Branches     4251     4251              
==========================================
- Hits        81953    81938      -15     
- Misses       1928     1942      +14     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.