ci: enable standalone sca system tests (#11769)

CI: Enables [system tests for Standalone SCA
billing](DataDog/system-tests#3690) to run on
dd-trace-py's CI

## 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
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- 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)

.github/workflows/system-tests.yml

@@ -213,6 +213,10 @@ jobs:
         if: always() && steps.docker_load.outcome == 'success' && matrix.scenario == 'appsec-1'
         run: ./run.sh IAST_STANDALONE
 
+      - name: Run SCA_STANDALONE
+        if: always() && steps.docker_load.outcome == 'success' && matrix.scenario == 'appsec-1'
+        run: ./run.sh SCA_STANDALONE
+
       - name: Run APPSEC_RUNTIME_ACTIVATION
         if: always() && steps.docker_load.outcome == 'success' && matrix.scenario == 'appsec-1'
         run: ./run.sh APPSEC_RUNTIME_ACTIVATION