Rollback Ruby injector update

[lloeki]

What does this PR do?

Revert the Ruby injector update.

Motivation:

• Test PR: would reverting work?
• Delta guidelines: ROLLBACK-PLAN procedure.
• Prepare in advance of release for a possible pull out of this feature, delaying it to January.

Change log entry

• SSI: rollback of deployment mode support

Additional Notes:

Based off #5170 to include all tests.

How to test the change?

CI

[github-actions]

👋 Hey @lloeki, please fill "Change log entry" section in the pull request description.

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**Change log entry**

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^{Visited at: 2025-12-19 11:01:11 UTC}

[datadog-datadog-prod-us1]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage
• Patch Coverage: 100.00%
• Overall Coverage: 95.26% (-0.01%)

View detailed report

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 4087390 | Docs | Datadog PR Page | Was this helpful? Give us feedback!}

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-12-19 11:26:31

Comparing candidate commit 4087390 in PR branch lloeki/revert-ruby-injector-update with baseline commit 2cb8be7 in branch master.

Found 1 performance improvements and 0 performance regressions! Performance is the same for 43 metrics, 2 unstable metrics.

scenario:tracing - Propagation - Trace Context

• 🟩 throughput [+3306.081op/s; +3416.823op/s] or [+9.745%; +10.071%]

[lloeki]

All signals green, rollback is confirmed effective on this branch.