LPS-38694 Subscriptions to content on private pages persist after leaving the site in the My Subscriptions portlet

Hey Hugo,

I'm sending this back through you so that we can get a fix out to the customer.

One simple way we might be able to remove the subscriptions without doing it when the user is removed from the site is in SubscriptionSender around line 457 where it checks to see if the user has permission. There, if it returns false instead of just logging a debug statement we could remove the subscription. Or in the plugin, when we check for permissions, if it returns false then we can remove the subscription. Just a couple of thoughts if the deletion is absolutely necessary for the fix for the client.