Disable page’s “page templates” in page attributes

theme_page_templates 
function hoge_remove_page_templates( $templates ) {
//    use unset() if you want to remove specific template
//    unset( $templates['page-templates/contributors.php'] );
//    return $templates;

//    or just return empty array to remove the entire page templates input 
    return array();
}
add_filter( 'theme_page_templates', 'hoge_remove_page_templates' );