fix(iast): remove unneeded atexit handler (#8565)

IAST: This fix addresses an issue where the atexit handler could lead to
a segmentation fault.

Fixes #8504

## Checklist
- [x] Change(s) are motivated and described in the PR description
- [x] Testing strategy is described if automated tests are not included
in the PR
- [x] Risks are described (performance impact, potential for breakage,
maintainability)
- [x] Change is maintainable (easy to change, telemetry, documentation)
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are followed or label `changelog/no-changelog` is set
- [x] Documentation is included (in-code, generated user docs, [public
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- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))
- [x] If this PR changes the public interface, I've notified
`@DataDog/apm-tees`.
- [x] If change touches code that signs or publishes builds or packages,
or handles credentials of any kind, I've requested a review from
`@DataDog/security-design-and-guidance`.

## Reviewer Checklist

- [x] Title is accurate
- [x] All changes are related to the pull request's stated goal
- [x] Description motivates each change
- [x] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- [x] Testing strategy adequately addresses listed risks
- [x] Change is maintainable (easy to change, telemetry, documentation)
- [x] Release note makes sense to a user of the library
- [x] Author has acknowledged and discussed the performance implications
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- [x] Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

(cherry picked from commit 9aaa7d4)

ddtrace/appsec/_iast/_taint_tracking/_native.cpp

@@ -63,9 +63,6 @@ PYBIND11_MODULE(_native, m)
 {
     initializer = make_unique<Initializer>();
     initializer->create_context();
-    // Cleanup code to be run at the end of the interpreter lifetime:
-    auto atexit = py::module::import("atexit");
-    atexit.attr("register")(py::cpp_function([] { initializer.reset(); }));
 
     m.doc() = "Native Python module";
 

releasenotes/notes/iast-fix-remove-unneeded-atexit-handler-2a2f7e193c457666.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    Vulnerability Management for Code-level (IAST): Fixes an issue where an atexit handler could lead to a segmentation fault.