Guard against scripts/styles being printed in SW at wp_enqueue_scripts action

[westonruter]

The service worker fires wp_enqueue_scripts action:

pwa-wp/wp-includes/class-wp-service-workers.php

Lines 118 to 144 in 943de6d

	if ( ! is_admin() ) {
	wp_enqueue_scripts();
	/**
	* Fires before serving the frontend service worker, when its scripts should be registered, caching routes established, and assets precached.
	*
	* @since 0.2
	*
	* @param WP_Service_Worker_Scripts $scripts Instance to register service worker behavior with.
	*/
	do_action( 'wp_front_service_worker', $this->scripts );
	} else {
	$hook_name = 'service-worker';
	set_current_screen( $hook_name );
	/** This action is documented in wp-admin/admin-header.php */
	do_action( 'admin_enqueue_scripts', $hook_name );
	/**
	* Fires before serving the wp-admin service worker, when its scripts should be registered, caching routes established, and assets precached.
	*
	* @since 0.2
	*
	* @param WP_Service_Worker_Scripts $scripts Instance to register service worker behavior with.
	*/
	do_action( 'wp_admin_service_worker', $this->scripts );
	}

As discovered in https://wordpress.org/support/topic/sevice-worker-error/ some sites may erroneously print scripts or styles at wp_enqueue_scripts when they should rather be using the wp_print_styles or wp_print_scripts actions (or even wp_head).

To guard against this, the above logic should be wrapped in output buffering to suppress any output and then clean the buffer.