title: In firebase authentication, is there a way to remove a custom claim?
body: <p>In order to set a custom claim, one uses:</p>
  
  <pre><code>admin.auth().setCustomUserClaims(uid,{claim:value});
  </code></pre>
  
  <p>There does exist </p>
  
  <pre><code>admin.auth().updateUser(uid,{claim:value});
  </code></pre>
  
  <p>...but I'm not exactly clear on how the two are different, and neither one seems to get at actually removing a previously applied custom claim.</p>