feat(devices): add Pontoon to client list (#5366), r=@vbudhram

app/images/icon-service-pontoon.svg

@@ -0,0 +1 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?><svg width="22" height="28" viewBox="0 0 22 28" xmlns="http://www.w3.org/2000/svg"><title>Slice 1</title><g fill="none" fill-rule="evenodd"><path d="M4 4h14v16H4V4zm0 16h4v8H4v-8z" fill="#EDEDED"/><path fill="#505050" d="M8 8h6v8H8zM8 20h4v8H8v-8zm14 0v4H12v-4h10zM0 0h4v28H0V0zm18 0h4v20h-4V0zM4 0h14v4H4V0z"/></g></svg>

app/styles/modules/_settings.scss

@@ -627,6 +627,10 @@ section.modal-panel {
   &[data-name='Firefox Notes'] {
     background-image: url('/images/icon-service-firefox-notes.svg');
   }
+
+  &[data-name='Pontoon'] {
+    background-image: url('/images/icon-service-pontoon.svg');
+  }
 }
 
 .client-webSession {