CI: move build_release to a namespace runner (#32675)

.github/workflows/selfdrive_tests.yaml

@@ -26,7 +26,9 @@ env:
 jobs:
   build_release:
     name: build release
-    runs-on: ubuntu-latest
+    runs-on: ${{ ((github.repository == 'commaai/openpilot') &&
+                   ((github.event_name != 'pull_request') ||
+                    (github.event.pull_request.head.repo.full_name == 'commaai/openpilot'))) && 'namespace-profile-amd64-8x16' || 'ubuntu-latest' }}
     env:
       STRIPPED_DIR: /tmp/releasepilot
     steps: