DEBUG-3700 more explicitly access active remote

[p-datadog]

What does this PR do?

Removes Datadog::Core::Remote.active_remote and friends and changes the callers of this method to use Datadog.send(:components, allow_initialization: false).

Motivation:
Making code that intends to read component state only do so, by passing allow_initialization: false option to Datadog.send(:components). The issue with unconditional initialization is described in #4619.

The code in this PR only acts when there is an active remote, and is not designed to initialize the tracer.

Change log entry
None

Additional Notes:
Related: #4641

How to test the change?
Existing tests

[github-actions]

Thank you for updating Change log entry section 👏

^{Visited at: 2025-05-28 19:02:57 UTC}

[datadog-datadog-prod-us1]

Datadog Summary

✅ Code Quality    ✅ Code Security    ✅ Dependencies

---

Was this helpful? Give us feedback!

[datadog-datadog-prod-us1]

Datadog Report

Branch report: components-init-remote
Commit report: 1f72ca6
Test service: dd-trace-rb

✅ 0 Failed, 21483 Passed, 1303 Skipped, 4m 1.21s Total Time

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-05-28 19:29:01

Comparing candidate commit 1f72ca6 in PR branch components-init-remote with baseline commit b76fbae in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 39 metrics, 6 unstable metrics.