Php 8.x compliance

[meyerauslander]

PHP has deprecated dynamic class props
Warning messages show up in the php error log. e.g.

 PHP Deprecated:  Creation of dynamic property WC_Taxjar_Integration::$method_description is deprecated in /var/www/html/wp-content/plugins/taxjar-simplified-taxes-for-woocommerce/includes/class-wc-taxjar-integration.php on line 39

This PR will prevent these warning messages.

Steps to Reproduce

• Access any site page.

Expected Result

Clean php error log.

Applies to any instance running PHP 8.2 and up

Solves the problem for all installations

[cla-assistant]

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[cla-assistant]

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