Remove WooCommerce Plugin Check

[chihsuan]

Description:

This is a follow-up to Issue #1170, where the Plugin Dependencies feature was introduced (thanks @ryanhungate for adding this! 🙏 ), but the existing WooCommerce plugin check was not removed.

Since WordPress now handles plugin dependencies natively, ideally, we don't need to check the plugin now.

Problem:

• Users with non-standard WooCommerce folder names still encounter error messages. Specifically, the Mailchimp for WooCommerce plugin is available in the WooCommerce onboarding wizard. However, when they use a custom folder name for WooCommerce, this causes an issue that users will get an error message.
• To bypass this error, I understand that users can define the RUNNING_CUSTOM_WOOCOMMERCE constant, but it's not a good user experience.
• Maintaining redundant code adds unnecessary complexity and potential points of failure.

Suggested Changes:

• Deprecate/remove the mailchimp_check_woocommerce_plugin_status and mailchimp_check_woocommerce_is_installed functions.

References:

• WordPress Plugin Dependencies