Favorite listings is the build-in feature in Vantage theme. But for some sites it is not needed.
Following PHP code snippet will disable Favorite Listings. You can add in a custom plugin or child theme functions.php file. Alternatively, Code Snippets plugin can be used (more details in the instruction).
add_filter( 'va_fave_listing_link', '__return_empty_string' );
add_filter( 'va_header_menu_primary_items_user', function( $fields ) {
unset( $fields['favorites'] );
return $fields;
} );