title: How to get url of uploaded media in supabase storage in flutter?
body: <p>In flutter for uploading image according to doc is</p>
  <pre><code>final avatarFile = File('path/to/file');
  final response = await supabase
    .storage
    .from('avatars')
    .upload('public/avatar1.png', avatarFile, fileOptions: FileOptions(
      cacheControl: '3600',
      upsert: false
    ));
  </code></pre>
  <p>So, how we can get the downloadUrl of this uploaded media ?</p>