Attestation scripts in CI should not compare directly against STDOUT

[ChrisPenner]

Currently in ci.yaml the success or failure of attestation checks is:

          RESULT=$(./scripts/proofs/tests.sh --check)
          echo "Test proof: $RESULT"
          if [[ "$RESULT" == "pass" ]]; then
            exit 0
          elif [[ "$RESULT" == "fail" ]]; then
            echo "::error::Tests previously FAILED. Fix and re-run './scripts/proofs/tests.sh'."
            exit 1
          else
            echo "::error::Test proof not found. Run './scripts/proofs/tests.sh', commit the proofs file, and push again."
            exit 1
          fi

If I want to run the script with --verbose when debugging it also means the CI job will never pass, since --verbose changes stdout.

likely:

1. the scripts should return their status via exit code
2. --verbose should likely output on stderr instead
3. the ci script should check against error code, not stdout.