chore(ci): remove unneeded permissions from system-tests subworkflow

Author: nccatoni

.github/workflows/system_tests.yml

@@ -33,9 +33,7 @@ jobs:
       DD_API_KEY: ${{ secrets.DD_API_KEY }}
       TEST_OPTIMIZATION_API_KEY: ${{ secrets.TEST_OPTIMIZATION_API_KEY }}
     permissions:
-      contents: read
       id-token: write
-      packages: write
     with:
       library: python_lambda
       binaries_artifact: binaries