title: How to get the email of any user in Firebase based on user id?
body: <p>I need to get a user object, specifically the user email, I will have the user id in this format:</p>
  
  <p><code>simplelogin:6</code></p>
  
  <p>So I need to write a function something like this:</p>
  
  <p><code>getUserEmail('simplelogin:6')</code></p>
  
  <p>Is that possible?</p>