[APPSEC-56683] Add appsec.auto_user_instrumentation.mode setting

[Strech]

What does this PR do?

Adds a new customer-facing setting for AppSec which is suppose to replace existing deprecated option. It will take precedence over existing setting and have different values.

Motivation:

This is a part of the automated user tracking functionality.

Change log entry

Yes. TO BE DONE

Additional Notes:

This setting immediately will be incorporated into existing code, so it will be fine to release it without an additional functionality.

How to test the change?

CI should be enough

[datadog-datadog-prod-us1]

Datadog Report

Branch report: appsec-56683-update-auto-user-instrumentation-mode-configuration
Commit report: 6d78f43
Test service: dd-trace-rb

✅ 0 Failed, 22094 Passed, 1476 Skipped, 6m 30.35s Total Time

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 94.79167% with 5 lines in your changes missing coverage. Please review.

Project coverage is 97.72%. Comparing base (a70cf66) to head (6d78f43).
Report is 11 commits behind head on master.

Files with missing lines	Patch %	Lines
...ib/devise/patcher/registration_controller_patch.rb	37.50%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4352      +/-   ##
==========================================
- Coverage   97.72%   97.72%   -0.01%     
==========================================
  Files        1368     1368              
  Lines       82998    83090      +92     
  Branches     4220     4224       +4     
==========================================
+ Hits        81113    81200      +87     
- Misses       1885     1890       +5     

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[pr-commenter]

Benchmarks

Benchmark execution time: 2025-02-06 21:19:59

Comparing candidate commit 6d78f43 in PR branch appsec-56683-update-auto-user-instrumentation-mode-configuration with baseline commit a70cf66 in branch master.

Found 1 performance improvements and 1 performance regressions! Performance is the same for 29 metrics, 2 unstable metrics.

scenario:profiler - Allocations ()

• 🟥 throughput [-467298.939op/s; -461037.790op/s] or [-13.977%; -13.789%]

scenario:profiler - sample timeline=false

• 🟩 throughput [+0.463op/s; +0.471op/s] or [+7.676%; +7.816%]