Don't show notifications about your own actions
To mitigate this, don't notify about your own actions.
This isn't perfect (we get the other-copies-of-the-window-open-in-other-tabs case wrong) but I think the case we get wrong is rare / not very important.
Test Plan: Submitted stuff, saw other users get notifications but not me.
Reviewers: btrahan, joshuaspence
Reviewed By: joshuaspence
Maniphest Tasks: T6559
Differential Revision: https://secure.phabricator.com/D11275