Support async attribute in non-HTML5 script tags

[tynanbe]

When a theme doesn't declare support for HTML5 scripts, WordPress outputs the code like this:

<script type="text/javascript" src="https://.../wp-includes/assets/js/comment-reply.min.js" id="comment-reply-js" async="async" data-wp-strategy="async"></script>

The tag currently gets incorrectly rewritten to:

<script data-optimized="1" type="litespeed/javascript" data-src="https://.../wp-content/litespeed/js/generatedname.js?ver=hash" id="comment-reply-js"="async" data-wp-strategy="async"></script>

With this change, users shouldn't have to e.g.

add_action( 'after_setup_theme', function() {
   add_theme_support( 'html5', [ 'script' ] );
}, 10 );