pin system tests to a specific commit (#6289)

Author: rochdev

.github/dependabot.yml

@@ -10,6 +10,7 @@ updates:
       - "/"
       - "/.github/actions/*"
       - "/.github/actions/*/*"
+      - "/.github/workflows/*"
     schedule:
       interval: "weekly"
     groups:

.github/workflows/system-tests.yml

@@ -31,10 +31,11 @@ jobs:
   main:
     needs:
       - build-artifacts
-    uses: DataDog/system-tests/.github/workflows/system-tests.yml@main
+    uses: DataDog/system-tests/.github/workflows/system-tests.yml@b2523d82a7fcffb5ca642ee7b76eb476fbef04fe
     secrets: inherit
     permissions:
       contents: read
+      id-token: write
       packages: write
     with:
       library: nodejs