message: Improve for `matrix`
diff: @@ -887,7 +887,7 @@ export async function uploadDebugArtifacts(
  }
  let suffix = "";
  const matrix = getRequiredInput("matrix");
  - if (matrix !== undefined && matrix !== "null") {
  + if (matrix) {
  for (const entry of Object.entries(JSON.parse(matrix)).sort())
  suffix += `-${entry[1]}`;
  }
  