fix: Ensure check_url_match function is defined only once

[jweston491]

Proposed changes

I'm using Bluehost, and the Bluehost plugin relies on this package as a dependency. When registering a new user in our app's frontend, we get this error:

PHP Fatal error: Cannot redeclare NewfoldLabs\WP\Module\ECommerce\check_url_match() (previously declared in /mysitepath/public_html/wp-content/plugins/bluehost-wordpress-plugin/vendor/newfold-labs/wp-module-ecommerce/includes/ECommerce.php:699) in /mysitepath/public_html/wp-content/plugins/bluehost-wordpress-plugin/vendor/newfold-labs/wp-module-ecommerce/includes/ECommerce.php on line 699

So this PR aims to fix that.

Type of Change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Video

Checklist

• I have read the CONTRIBUTING doc
• I have viewed my change in a web-browser
• Linting and tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)