Fix debug.log warnings - session already started and headers being already sent

[kimhornung]

I have a custom theme that has user logins and related code where I use the PHP session.
In such a case, the SCORM Cloud plugin causes warnings to be written to the log file when WP debug is enabled.

Steps to reproduce

1. Add the following lines to wp-config.php to enable WP debug

define('WP_DEBUG', true);
define('WP_DEBUG_DISPLAY', false);
define('WP_DEBUG_LOG', true);

2. Add the following lines to your theme's functions.php

function theme_start_session() {
	if ( ! session_id() && ! headers_sent() ) {
		session_start();
	}
}
add_action('init', 'theme_start_session');

3. Visit any page on the website or in the admin.

4. Also trigger WP cron by visiting "/wp-cron.php?doing_wp_cron=1667920617.6225979328155517578125"

5. Check /wp-content/debug.log

Result:
The following warnings appears in the log file:

[08-Nov-2022 15:23:57 UTC] PHP Notice:  session_start(): A session had already been started - ignoring in <webroote>/scormcloud/scormcloudcontenthandler.php on line 239
[08-Nov-2022 15:23:57 UTC] PHP Warning:  Cannot modify header information - headers already sent by (output started at <webroot>/scormcloud/scormcloudcontenthandler.php:239) in <webroot>/wp-includes/pluggable.php on line 1421