Improve tracer state detection

[Anilm3]

Description

This PR fixes two different problems:

• Distinguishing between the tracer being enabled and being loaded, the former shouldn't prevent appsec from loading symbols while the latter should.
• Obtaining the correct tracer enabled state during the request lifecycle.

Related ticket: APPSEC-11407

Motivation

Additional Notes

Describe how to test your changes

Readiness checklist

• Unit tests have been updated and pass
• If known, an appropriate milestone has been selected
• All new source files include the required notice

Release checklist

• The CHANGELOG.md has been updated

[codecov-commenter]

Codecov Report

Merging #305 (9af4cff) into master (3a42eb1) will increase coverage by 8.03%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #305      +/-   ##
==========================================
+ Coverage   64.15%   72.19%   +8.03%     
==========================================
  Files          95       25      -70     
  Lines        6026     3438    -2588     
  Branches     1952      787    -1165     
==========================================
- Hits         3866     2482    -1384     
+ Misses       1008      562     -446     
+ Partials     1152      394     -758     

Flag	Coverage Δ
extension	72.19% <66.66%> (-0.04%)	⬇️
helper	?

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Files	Coverage Δ
src/extension/user_tracking.c	67.92% <100.00%> (ø)
src/extension/ddtrace.c	66.86% <83.33%> (+0.39%)	⬆️
src/extension/ddappsec.c	77.82% <0.00%> (ø)

... and 71 files with indirect coverage changes

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