Can I change the URL from http to https in the theme file?
Looks like a bug in the theme. It shouldn’t be a URL, just a reference to the icon.
To fix it you can make a change in the core file /CP9/framework/new_class/ppt.php.
Open up the file and look around line #179 for:
'menu_icon' => "dashicons dashicons-megaphone", and remove the first dasicons.
It should look like:
'menu_icon' => "dashicons-megaphone",