chore(ci): remove python 3.9 from appsec_aggregated_leak_testing (#11154

)

Remove python 3.9 from appsec_aggregated_leak_testing

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
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- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
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[release branch maintenance
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.gitlab/tests/appsec.yml

@@ -56,7 +56,7 @@ appsec threats fastapi:
 
 appsec aggregated leak testing:
   extends: .test_base_hatch
-  parallel: 4
+  parallel: 3
   variables:
     SUITE_NAME: "appsec_aggregated_leak_testing"
   retry: 2

hatch.toml

@@ -357,7 +357,7 @@ test = [
 ]
 
 [[envs.appsec_aggregated_leak_testing.matrix]]
-python = ["3.9", "3.10", "3.11", "3.12"]
+python = ["3.10", "3.11", "3.12"]