title: FCM Notification color attribute is not working
body: <p>Using the following payload syntax I am trying to achieve a coloured notification:</p>
  
  <pre><code>const payload = {
    notification : {
      title : "App title",
      body : "You have new messages",
      icon : "not_icon_white2",
      color : "#2a6d57",
      sound : "default",
      click_action : "do something"
    }
  };
  </code></pre>
  
  <p>The icon in the status bar is displayed correctly (as white) yet in the notification drawer my notification behaves like this:
  <a href="https://i.stack.imgur.com/rRy8D.png" rel="noreferrer"><img src="https://i.stack.imgur.com/rRy8D.png" alt="enter image description here"></a></p>
  
  <p>The title color is correct, yet the notification icon remains white, resulting in a poor visual experience. </p>
  
  <p>I am using (as you can see above) the <code>color</code> attribute in the payload that should change the color of the icon as well.</p>
  
  <p>Official docs:</p>
  
  <blockquote>
    <p>color
    Optional, string
    The notification's icon color, expressed in #rrggbb format. </p>
  </blockquote>
  
  <p><strong>Why is the notification icon color not changing to the color I specified in the payload?</strong></p>
  
  <p>Could the icon drawable (a white one with transparent portions) be the cause here?</p>
  
  <p>NOTE: This question regards FCM <strong>notification payload</strong> and <strong>NOT</strong> data. Also, the question regards the background case of sending the content, not foreground.</p>