How to download Firebase Test Lab matrix artifacts?

Question

Is there a way to download Firebase Test Lab matrix artifacts using Cloud Functions and probably save ourselves the trouble of creating another service account to authenticate with GCloud CLI?

exports.testMatrixCompletion = functions.testLab.testMatrix().onComplete(testMatrix => {

    // TestMatrix captures details about a test run: https://firebase.google.com/docs/reference/functions/firebase-functions.testlab.testmatrix
    const matrixId = testMatrix.testMatrixId;

    switch (testMatrix.state) {
        case 'FINISHED':
            console.log(`Test matrix ${matrixId} finished with outcome: ${testMatrix.outcomeSummary}`);
            break;
        case 'INVALID':
            console.log(`Test matrix ${matrixId} was marked as invalid: ${testMatrix.invalidMatrixDetails}`);
            break;
        default:
            console.log(`Test matrix ${matrixId} completed with state ${testMatrix.state}`);
    }

    console.log(`Test matrix ${matrixId} completed with client details ${testMatrix.clientInfo}`);

    if (!!testMatrix.resultStorage.resultsUrl) {
        console.log(`Test results are available at ${testMatrix.resultStorage.resultsUrl}`);
    }

    // TODO: Cache the test matrix results and store it to a cloud storage solution where download url of files are accessible for public,
    // one quick solution is to use Firebase Cloud Storage here to avoid extra authentication with tools like GCloud CLI and get the download url after success upload.
    

    return true;

});

Currently we have this simple setup and we are hoping to download files from here.