sudo/doas check too global

[jshufro]

https://github.com/rocket-pool/smartnode-install/commit/64f1406e56fd6e54253c29361a61c4b5525df48c elevated the sudo/doas check to the top level of the script, but since it's only used when -d isn't passed, that's a bit too universal.

Perhaps that commit should be reverted and detect_sudo_command >&2 should be invoked just after if [ -z "$NO_DEPS" ]; then and before the case statements