Dismiss a task

Dismisses the task: it closes, its unsent notices are cancelled, and nothing else changes. Auto Generate acts on an invoice only when it first arrives, so it does not come back to this one; its payment links are still created by a person. Existing links and payments are not changed. A dismissed task never comes back, so obtain the user's approval before calling. Dismissing a dismissed task changes nothing.

Requires an admin API key (has side effects).