Shop as a Customer for WooCommerce 1.3.3

* Prevented plugin scripts from loading for normal visitors

* Fixed the issue where the customer's cart would get emptied when the admin switched back from customer view.
* Minor bug fixes

* Added option to search customers by company, address, phone
* Added option to send order invoice to customers on thankyou page
* Minor bug fixes

* Added compatibility fix for php8 : Null value exceptions on array count
* Minor vulnerability issues fixes