Wordpress - Text Widget creates a <li>

This seems to occur when you leave out 'before_widget' and 'after_widget' in the array when you register your sidebar/widget. I had the same problem and fixed it by leaving them blank.

register_sidebar( 
    array(  
        'name' => 'Footer Widget',
        'id' => 'footer-widget-1',
        'class' => 'footer-widget',
        'description' => 'Footer widget',
        'before_widget' => '',
        'after_widget' => '',
        'before_title' => '<h3>',
        'after_title' => '</h3>',
    ) 
);

I think WordPress widgets create li tags on default. If you want the bullet points removed you could fix that with a css approach.

.widget li {
  list-style: none;
}