By default send cancel req. to payment processor

By default send cancel req. to payment processor

When cancelling a payment through the Civi interface, the cancellation
request should be sent to the payment processor by default. To that end,
I've set the "Yes" option to be selected by default on the recurring
contribution cancellation form.

When using a payment processor such as TrustCommerce, they need to know
about the cancellation in order to stop future payments.