suppress cancel auto-renewal admin link if not valid for select processor

On the membership tab we expose a link to "cancel auto-renewal" for memberships configured with the auto-renewal feature. That link is exposed even when the payment processor used for the transaction does not support admin cancellation.

For example, auto-renewal can be constructed via PayPal standard, but the auto-renewal cancellation link only supports PayPal Pro (see CRM_Core_Payment_PayPalImpl::cancelSubscription() where the payment processor type must be PayPal – which refers to PayPal pro).

Triggering the cancellation does yield an interface message ("The recurring contribution could not be cancelled."), but there is no further information, so the user is left confused as to why it did not work. It would be preferred to simply suppress the option altogether.