Fix benchmark_manifest_ops.py sandboxing

[mrjf]

The script scripts/benchmark_manifest_ops.py exists in the repository. A local run was attempted but could not complete (permission denied in the sandbox environment).

Make it so we can run this in CI and generate the results for https://githubnext.github.io/apm/

[mrjf]

Closing as part of resetting githubnext/apm to match the current state of upstream microsoft/apm. The Python-to-Go migration experiment has been wound down. See commit ccdafc4 on main.