How do I create WordPress Authors Dropdown with links

I could be wrong as I don’t know how WordPress controls the dropdown menu but looks like it could be only returning a name of the author and not a link to their page.

I have tested the below code in a WordPress site environment and works including linking to the authors page.

   <select name="author-dropdown" id="author-dropdown--1" onchange="document.location.href=this.options[this.selectedIndex].value;">
<option value=""><?php echo esc_attr( __( 'Select Author' ) ); ?></option> 
<?php 
// loop through the users
$users = get_users('role=author');
foreach ($users as $user) 
{
    if(count_user_posts( $user->id ) >0)
    {
      // We need to add our url to the authors page
      echo '<option value="'.get_author_posts_url( $user->id ).'">';
      // Display name of the auther you could use another like nice_name
      echo $user->display_name;
      echo '</option>'; 
    } 

}
?>
</select> 

Added update for making sure the authors have post and then added on administrator not sure how to combine the two roles without doing a duel foreach

<select name="author-dropdown" id="author-dropdown--1" onchange="document.location.href=this.options[this.selectedIndex].value;">
    <option value=""><?php echo esc_attr( __( 'Select Author' ) ); ?></option> 
    <?php 
    // loop through the users
    $users = get_users('role=author');
    foreach ($users as $user) 
    {
        // get user who have posts only
        if(count_user_posts( $user->id ) >0)
        {
          // We need to add our url to the authors page
          echo '<option value="'.get_author_posts_url( $user->id ).'">';
          // Display name of the auther you could use another like nice_name
          echo $user->display_name;
          echo '</option>'; 
        } 

    }

$users = get_users('role=administrator');
    foreach ($users as $user) 
    {
        // get user who have posts only
        if(count_user_posts( $user->id ) >0)
        {
          // We need to add our url to the authors page
          echo '<option value="'.get_author_posts_url( $user->id ).'">';
          // Display name of the auther you could use another like nice_name
          echo $user->display_name;
          echo '</option>'; 
        } 

    }
    ?>
    </select>