Prefer environment variables to interpolation in GitHub actions

[iskiselev]

Per @martincostello in #5002:

Use environment variables such as ${env:GITHUB_ACTION_PATH} is preferable to interpolation as it removes any possibility of shell injection and makes it easier to copy-paste snippets to terminals for testing.
Same here with interpolation. Either assign them to env vars and use those, or maybe they'll be available already as ${env:INPUT_NAME} like ${env:INPUT_ENVIRONMENT-TYPE} (I can't remember if that's a thing or not).
${{ and }} isn't needed for if:.
Is Path.IsPathRooted() available to the PowerShell version on the runners?
Shouldn't this be a Windows form of path? (/c/ProgramData/OpenTelemetry .NET AutoInstrumentation/logs)

[pellared]

Consider adding https://github.com/zizmorcore/zizmor (or something similar) to CI as they can help finding possible injections (e.g. see: https://docs.zizmor.sh/audits/#template-injection).
It is already used in OBI: https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation/blob/main/.github/workflows/check_gh_actions_security.yml