DEBUG-3457 start DI probe notifier worker on every event submission

[p-datadog]

What does this PR do?
Alternative implementation to #4358, this PR checks if the probe notifier worker is running on every event submission and starts it if the process forked.

Motivation:
DI is not submitting events to backend in some forked server configurations.

Change log entry
Yes: fix dynamic instrumentation event submission on forked servers

Additional Notes:

How to test the change?
Tested manually against debugger-demo-ruby

[datadog-datadog-prod-us1]

Datadog Report

Branch report: di-worker-2
Commit report: b0e9005
Test service: dd-trace-rb

✅ 0 Failed, 22072 Passed, 1477 Skipped, 5m 47.77s Total Time

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.74%. Comparing base (5319afc) to head (b0e9005).
Report is 18 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4363      +/-   ##
==========================================
+ Coverage   97.73%   97.74%   +0.01%     
==========================================
  Files        1348     1348              
  Lines       82508    82511       +3     
  Branches     4199     4199              
==========================================
+ Hits        80636    80650      +14     
+ Misses       1872     1861      -11     

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

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-02-11 00:04:44

Comparing candidate commit b0e9005 in PR branch di-worker-2 with baseline commit 5319afc in branch master.

Found 2 performance improvements and 0 performance regressions! Performance is the same for 29 metrics, 2 unstable metrics.

scenario:tracing - 10 span trace - no writer

• 🟩 throughput [+148.811op/s; +152.976op/s] or [+5.366%; +5.516%]

scenario:tracing - 100 span trace - no writer

• 🟩 throughput [+19.964op/s; +20.808op/s] or [+6.024%; +6.278%]