Allow Script Tags to be added in content for specific user roles. Works will multisite as well.

allow-script-tag-for-specific-user-roles.php

<?php
/**
 * Allow Script Tags to be used in editor for Administrator user role.
 *
 * @author Mehul Gohil <hello@mehulgohil.com>
 */
function allow_unfiltered_html_for_administrators( $allowed_tags ) {
	// Bailout, if the logged-in user role is not `administrator`.
	if ( ! current_user_can( 'administrator' ) ) {
		return $allowed_tags;
	}

	$allowed_tags['script'] = array(
		'src'     => true,
		'height'  => true,
		'width'   => true,
		'charset' => true,
		'async'   => true
	);
  
	return $allowed_tags;
}

add_filter( 'wp_kses_allowed_html', 'allow_unfiltered_html_for_administrators' );