[DOCS] for sample: taskqueues-backup-images, not clear how to set up "impersonation" permission about functions-samples

[gazialankus]

I have enabled logs for the task and I'm getting a 401

{
  "textPayload": "The request was not authorized to invoke this service. Read more at https://cloud.google.com/run/docs/securing/authenticating Additional troubleshooting documentation can be found at: https://cloud.google.com/run/docs/troubleshooting#401",
  "insertId": "646f8e03000a6f22b18e5817",
  "httpRequest": {
    "requestMethod": "POST",
    "requestUrl": "...",
    "requestSize": "1575",
    "status": 401,
    "userAgent": "Google-Cloud-Tasks",
    "remoteIp": "35.243.23.219",
    "serverIp": "216.239.36.54",
    "latency": "0s",
    "protocol": "HTTP/1.1"
  },
  "resource": {
    "type": "cloud_run_revision",
    "labels": {
      "configuration_name": "synchronizetask",
      "revision_name": "synchronizetask-00003-doq",
      "service_name": "synchronizetask",
      "project_id": "...",
      "location": "us-central1"
    }
  },
  "timestamp": "2023-05-25T16:34:11.682815Z",
  "severity": "WARNING",
  "labels": {
    "goog-managed-by": "cloudfunctions"
  },
  "logName": "projects/.../logs/run.googleapis.com%2Frequests",
  "trace": "projects/.../traces/36c6c7d9ced30537f7ee2925be9bd7ad",
  "receiveTimestamp": "2023-05-25T16:34:11.694423190Z",
  "spanId": "8111407204631128905"
}

[gazialankus]

What worked for me was to go to Cloud Functions in Google Cloud Console, select the task function that was created with onTaskDispatched, and give Cloud Functions Admin role to the Firebase Service Account. I hope this helps someone. This was a very easy thing to do and docs were unnecessarily cryptic. If this is too broad of a permission, it is upon the docs authors to clearly present what's needed.