title: Cloud composer: "PERMISSION_DENIED: The caller does not have permission"
body: <p>I implemented a few tasks with BashOperator. Ones with "gsutil rm" and "gsutil cp" worked fine. But one with "gcloud alpha firestore export" generates this error:</p>
  
  <pre><code>{bash_operator.py:101} INFO - ERROR: (gcloud.alpha.firestore.export) PERMISSION_DENIED: The caller does not have permission
  </code></pre>
  
  <p>This command itself works fine in gcloud shell. I tried to give some Firestore related permissions to the service account used by the Composer but it still doesn't work. Any idea</p>