Background
When creating webhooks on a site without the Discourse Category Experts plugin installed, the category_experts_unapproved_event and category_experts_approved_event webhook events are getting automatically added to webhooks without a way to disable them.
The category_experts_unapproved_event and category_experts_approved_event webhook events are associated with the Discourse Category Experts plugin so I am moving these webhook events into the Category Experts plugin.
Changes
This PR deletes Category Experts plugin specific webhook event types added into core.