Webhook application id is compared by reference rather than by value

Application service generic does

if (application.getId() == webhook.getApplication().getId())

in findWebhookById() and unregisterWebhook(), and both sides of the comparison are Long, so we're comparing references instead of comparing values.

This works accidentally as long as we haven't created 127 or more applications (due to the JVM caching instances of Long which are between -128 and 127), but after that it falls over.