chore(ci): use dd-sts for system-tests test optimization

Author: nccatoni

.github/workflows/dev.yml

@@ -202,10 +202,12 @@ jobs:
       TEST_OPTIMIZATION_API_KEY: ${{ secrets.DD_CI_VIS_API_KEY }}
     permissions:
       contents: read
+      id-token: write
       packages: write
     with:
       library: cpp
       binaries_artifact: system_tests_binaries
       parametric_job_count: 8  # dedicated parameter to speed up parametric job
       scenarios: PARAMETRIC
       push_to_test_optimization: true
+      dd_sts_policy: dd-trace-cpp-system-tests