Add nightly system-tests configuration

Run the tracer_release scenario group on schedule and push to main,
keep appsec for pull requests. Upload all results to Test Optimization.

Made-with: Cursor

Author: nccatoni

.github/workflows/system_tests.yml

@@ -7,6 +7,7 @@ on:
   pull_request:
     branches:
       - "**"
+  workflow_dispatch: {}
 
 jobs:
   build:
@@ -27,12 +28,15 @@ jobs:
     needs:
       - build
     uses: DataDog/system-tests/.github/workflows/system-tests.yml@main
-    secrets: inherit
+    secrets:
+      DD_API_KEY: ${{ secrets.DD_API_KEY }}
+      TEST_OPTIMIZATION_API_KEY: ${{ secrets.DD_API_KEY }}
     permissions:
       contents: read
       packages: write
     with:
       library: python_lambda
       binaries_artifact: binaries
-      scenarios_groups: appsec
+      scenarios_groups: ${{ (github.event_name == 'push' || github.event_name == 'workflow_dispatch') && 'tracer_release' || 'appsec' }}
       skip_empty_scenarios: true
+      push_to_test_optimization: true