Make ACTION_NOTHING a "standard" action in Herald
Summary: Ref T8455. Multiple adapters implement essentially identical effects for ACTION_NOTHING. Consolidate them.
Test Plan: Created several ACTION_NOTHING rules and updated the corresponding objects.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T8455
Differential Revision: https://secure.phabricator.com/D13178