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

Author: nccatoni

.github/workflows/run-system-tests.yaml

@@ -79,6 +79,7 @@ jobs:
       excluded_scenarios: APM_TRACING_E2E_OTEL,APM_TRACING_E2E_SINGLE_SPAN,PROFILING  # exclude flaky scenarios
       skip_empty_scenarios: true
       push_to_test_optimization: true
+      dd_sts_policy: dd-trace-java-system-tests
 
   # Ensure the main job is run to completion
   check: